In many democratic countries there is some sort of a right for an accused to not have to answer police questions to prevent people being forced to incriminate themselves. In the USA this is in the 5th amendment of the constitution, in the UK it is the right to silence on arrest.

In some cases there are exceptions to this right, frequently associated with immunity from prosecution for the information provided. An example of this is the UK Terrorism Act 2000, paragraph 18 of which makes it is crime to not answer questions, but paragraph 5A (1) provides immunity from prosecution. As I understand it there is a similar exception to the 5th amendment in the US.

This may at first glance appear to provide suitable protection, but it seems the logic breaks down in the presence of multiple legal jurisdictions that may not recognise the immunity. In the UK this is recently demonstrated when police used these powers to investigate someone involved in the unrest in France. In the US with 50 different state jurisdictions, the federal government as well as many others such as Native reservations this must come up frequently.

What is the logic about how it is supposed to work? What happens in practice when such information is used in a different jurisdiction to where immunity is granted?

  • 5
    Is this not a better fit for law.stackexchange?
    – wonderbear
    Apr 29, 2023 at 19:12
  • There is no logic and no automatic offset or exclusion, although there of course can be legally binding agreements. But the person testifying will need to ensure it applies where they want it to, not the other side(s).
    – jmoreno
    Apr 30, 2023 at 21:05

3 Answers 3


Frame challenge: I don't quite see what different jurisdictions has to do with this. The UK charged him for an alleged crime committed in the UK (obstruction of justice by failure to disclose something to UK police) regardless of what he didn't disclose, which was something [indirectly] about stuff that happened in France--and I say "indirectly" because the UK charge was apparently about not disclosing his phone password to UK police. He was not charged in the UK for failing to disclose something to the French police, AFAICT. So I don't see what "logic breaks down".

As far as jurisdiction goes, it's not different from the FBI charging a Russian with lying to the FBI about stuff that happened in Russia. Sometimes such questions can seem entirely legitimate (e.g. imagine "did you talk to someone in the FSB HQ in Moscow before coming here with a suitcase of cash"?) But of course, since lying [to the Feds] about any topic is indictable (like "what color was the condom you used yesterday in Moscow?"), it can be used for "gotcha" questions that might otherwise provide no indictable information if answered truthfully.

Whether the obstruction charge will stick in [a UK] court is another matter. Aside, there are various articles in the US press about obstruction of justice being a possibly charge there too for not disclosing a phone password, but they don't mention any concrete cases. (There is a later [2020] article that says that the Supreme Court of New Jersey has decided in a 4-3 vote that not giving your phone password is obstruction. SCOTUS denied certiorari on that case in 2021.) OTOH guilty verdicts in rather similar (phone password) cases have been handed down in the UK. (The defendant in that case also lost a fist appeal and announced appealing to the UK Supreme Court, but I've not been able to find any further info on the aftermath.) I suspect that in general the law [and its case law wrt passwords] was not overturned because a UK police FAQ still says:

Can the police demand passwords for electronic devices ?

Yes. If a person is being examined, they can be required to provide any information requested, including passwords and PINs to any electronic devices. They will commit an offence if they wilfully fail to comply with this requirement.

The UK law applicable is less straightforward (than lying to the FBI) because the "schedule 7" investigation has to be plausibly linked to terrorism, which I suspect is more debatable when it comes to protests in France. I suspect the real challenge in court is probably going to be on that angle, on the case you've brought up.

From the press reporting you've linked, it's not even clear if the French claimed their investigation had anything to do with terrorism, or if that was decided UK-side. The BBC's reporting on that precise issue is also a bit ambiguous:

Officers said they were stopping him under Schedule 7 of the Terrorism Act 2000 - this gives the police wide powers to search people at border crossings to check if they are involved in terrorism.

The police do not need any grounds to stop and search people at borders under these powers.

So it may have been entirely a UK decision to throw the terrorism angle at him. Even his lawyers didn't say that France alleged terrorism involvement. In fact, they complained that he was given "no justification or explanation" for the password request:

"It was demanded that he give up his phone and pass codes to the officers, with no justification or explanation offered. This morning, Ernest was formally arrested and transferred to a police station, accused of obstruction because of his refusal to give up his pass codes."

Finally, I suppose a valid concern may be that a country with a law like the UK's may communicate information from the "answers forced under penalty of obstruction" to another country [like France], who'd then prosecute. That is a possibility, but it may also be possible to claim in defense that [in this case in France] that the information was indeed forced, so inadmissible. Whether that would carry legal water, depends on minutia of the specific country's legal system (as is evident in the New Jersey case, for instance.) OTOH, the ECHR has held a rather dim view of shenanigans involving documentation/evidence obtained that way:

Funke v France represents the European Court's earliest affirmation of right to silence protections under the Convention. French Customs authorities had sought various financial records in connection with an investigation into the violation of French Customs regulations. Funke was fined for failing to turn over the sought-after documents, but the Court concluded that the procedure involved impermissible compulsion to produce self-incriminatory information in violation of the Convention.

"being unable or unwilling to procure [the documents] by some other means, [the government] attempted to compel the applicant himself to provide the evidence of offences he had allegedly committed. The special features of customs law . . . cannot justify such an infringement of the right of anyone 'charged with a criminal offence', within the autonomous meaning of this expression in Article 6 , . . ., to remain silent and not to contribute to incriminating himself.


Both Heaney v Ireland and Quinn v Ireland involved the application of an Irish law that criminalised the refusal of a suspect to answer police questions concerning crimes under the Offences Against the State Act 1939. The Irish State's attempt to justify using the threat of criminal punishment to compel potentially self-incriminatory evidence on the grounds that "the information sought could be essential for the investigation of serious and subversive crime" was rejected by the Court. In its ruling the Court took the position that:

"the security and public order concerns relied on by the State cannot justify a provision which extinguishes the very essence of the applicants' rights to silence and privilege against self-incrimination guaranteed by Article 6.1 of the Convention."

When information is sought by the State for purposes that are not strictly or solely, criminal, the applicable analysis is more complex. In some cases of this sort of criminal prosecution may lie just beneath the surface. Such was the case in Saunders v United Kingdom, where the United Kingdom Department of Trade and Industry (DTI) undertook an investigation of an illegal stock support scheme implemented by Saunders in connection with a corporate takeover. Saunders complied with a directive that he answer potentially self-incriminatory questions under threat of contempt, and his responses were used at his subsequent criminal prosecution for violating the Companies Act of 1985. However, this was held by the European Court to violate Art.6(1) of the Convention.

As far ECHR is concerned, it would probably make no difference that information is compelled in the UK, but then used in a criminal trial in France, but that [2007] paper doesn't discuss any such [cross-border] cases, perhaps because none had reached ECHR by then.

There is however this interesting case that adds some nuance to where the ECHR saw a limit to self-incrimination defense:

[In] Serves v France [...] a French officer and several comrades had been charged in connection with a homicide. However, because of a procedural irregularity, the initial judicial investigation and all subsequent proceedings were declared void. This was followed by a second investigation in which Serves, grior to being recharged in connection with the homicide, was called to appear before a military investigating judge as a witness in the case on three separate occasions. Each time he refused to take the oath and give evidence as a result of which he was subjected to three separate fines. Serves claimed this to be a breach of his Art.6.1 [...], but the European Court disagreed. Although the Court recognized that Serves had a legitimate concern that some of the evidence he might have provided could have been self-incriminatory, it concluded that the proper response would have been for him "to have refused to answer any questions from the judge that were likely to steer him in that direction". Refusing to take the oath and answer all questions, however, was not a permissible option. In the Court's view, the French procedure involving fines for refusing to appear did not represent impermissible compulsion to answer potentially incriminating questions, but rather was only a means of ensuring truthful responses.

I don't know if any [phone] password compulsion cases have reached the ECHR. It's not exactly clear how that would be decided just based on precedent, because e.g.

Despite Funke, the status of efforts to compel the production of documents under the Convention is unclear. In Saunders the European Court stated that right to Silence protections are inapplicable to demands for: I

Material which may be obtained from the accused through the use of compulsory powers but which has an existence independent of the will of the suspect, inter alia, documents acquired pursuant to a warrant, breath, samples and bodily tissue for the purpose of DNA testing.

And the UK in particular seems to have taken an interpretation that would allow them to get such documents in such manner:

an Attorney General's Reference [(No.7 of 2000), Re, (2001) 2 Cr. App. R. 19] in the United Kingdom took the position that the decision European Court are inapplicable to all efforts to compel the production of documents, whether by subpoena or warrant, as long as they contain no compelled statements of the accused.

And in Nov 2022, French courts have held rather similarly wrt to phone passwords, specifically

The French Court of Cassation has ruled that people who are suspected or accused of a crime are obliged to reveal the passcode of their mobile phone to the investigative authorities. The Court found that a mobile phone passcode can be considered a “secret decryption agreement of a means of cryptology” (convention de déchiffrement d’un moyen de cryptologie). Refusing to hand over the passcode of a mobile phone is punishable by a fine of up to 270,000 EUR or three years’ imprisonment. This punishment is increased to a fine of 450,000 EUR or five years’ imprisonment where revealing a passcode and giving access to the content of the mobile device could have prevented a criminal offence or reduced its impact.

That article also notes laconically that

“Decryption orders” in France are currently under review before the European Court of Human Rights in the case of Minteh v. France.

So, as a kind of summary here:

  • Whatever that guy told the UK police under the compelled inquiry would be protected from use in a criminal trial (almost certainly anywhere) under ECHR jurisdiction.

  • Not surrendering his phone password to the UK authorities [which is what he was charged for] is perhaps not terribly relevant [for the cross-border aspect], since French laws currently allow direct (NJ-style) compulsion (and probably with greater penalties for non-compliance). Although the ECHR seems has yet to rule on such "decryption orders".


It's quite different - In the US the Right to not Incriminate self is "absolute" in the sense that your choice to not answer investigators, or testify, cannot be used as a proof of some guilt against you by the judge (exceptions to the US 5th amendment exist but nevertheless the Right against self-incrimination in the US is really strong in practice, compared to other countries).

This has been reinforced in the US Supreme Court judgements of Griffin v. California, 380 U.S. 609 (1965), where it it was ruled that if any accused invokes his right against self-incrimination, a judge or a prosecution cannot instruct a jury that the silence of the accused was an admission of guilt.

In the UK or India, choosing not to answer or testify to something can be considered evidence of some guilt, and used negatively against you during trial for the crime you are being tried for.

This is evident from the Miranda warning the US police use:

“You have the right to remain silent. Anything you say can and will be used against you in a court of law. You have a right to an attorney. If you cannot afford an attorney, one will be appointed for you.”

versus the UK version of it:

“You do not have to say anything. But, it may harm your defence if you do not mention when questioned something which you later rely on in court. Anything you do say may be given in evidence.”

The UK government advisories on this subject clearly highlight that staying silent may not necessarily be the best legal option - you do not have to answer the questions but there could be consequences if you do not.

The UK's Criminal Justice and Public Order Act 1994 provides statutory rules under which adverse inferences may be drawn from the silence of an accused by the investigators and / or the court.

Canada seems to draw on aspects of both US and UK laws when it comes to Right against self-incrimination. In R. v. Noble the Canadian Supreme Court ruled that the Right to silence is absolute, and the silence of an accused cannot be used against them or be used for concluding his guilt beyond reasonable doubt:

The right to silence, which has been recognized as a principle of fundamental justice under s. 7 of the Canadian Charter of Rights and Freedoms, is based on society’s distaste for compelling a person to incriminate him‑ or herself with his or her own words. Just as a person’s words should not be conscripted and used against him or her by the state, it is equally inimical to the dignity of the accused to use his or her silence to assist in grounding a belief in guilt beyond a reasonable doubt. The presumption of innocence, enshrined at trial in s. 11(d) of the Charter, provides further support for this conclusion. In order for the burden of proof to remain with the Crown, the silence of the accused should not be used against him or her in building the case for guilt.

But, the Canadian Supreme Court has also ruled that accused don't have the right to have a lawyer during questioning.

As for the logic behind the variance of how the right is applied (or diluted), it can be partly explained with the politics of policing:

The Right to arms in the US has promoted a gun culture in the United States and thus policing an American community is more of an adversarial activity due to the dangers of gun violence. American police treat suspects with cautious hostility, often carry arms with them, are allowed to use it lethally in confrontations and the American public is encouraged to be docile and compliant in following any police orders so as to not "provoke" the American police. In some parts of America, policing is also done by elected officials. Prosecution is also done by elected officials. This often introduces a political bias in policing and prosecution.

Thus, it can be seen how a stronger Right against self-incrimination would be more desirable by the American public in such a political environment.

Where as in UK or India, community policing is the norm and police often don't carry guns with them. The police are expected to show high restraint in any confrontation with the public. And use of violence without prior permission is highly frowned upon.

On a similar note, many countries do not recognize the US legal doctrine of "Fruit of the poisonous tree" and any evidence, even if discovered illegally. is mostly admissible in many non-US courts.

  • I was under the impression that witness immunity was an exception to this: "The grant of immunity impairs the witness's right to invoke the Fifth Amendment protection against self-incrimination".
    – User65535
    Apr 30, 2023 at 17:11
  • 1
    @User65535 I believe it is because in such cases you voluntarily waive away the 5th amendment protection by being willing to testify in return for immunity. Once you voluntarily talk, and incriminate yourself on something not covered under the immunity protection offered, the law is free to prosecute you for these crimes.
    – sfxedit
    Apr 30, 2023 at 17:46
  • "As for the logic behind the variance of how the right is applied" This is incorrect. The 5th amendment was constitutional law prior to the rise of modern policing in the U.S. The logic behind it is rooted in the nature of grievances against the Crown that lead to the Revolutionary war, which was a bitter memory for those drafting the bill of rights amendments. It was inherited from British Common law and had been law for nearly 200 years prior to the Revolution.
    – hszmv
    May 2, 2023 at 12:26
  • @hszmv To clarify, I do not claim that the politics of policing and prosecution is the only reason that explains why there is a difference in the application of the law. But it certainly can be considered as one of the major factors that explains it. All of us (you, me and the questioner) are clear that the law has existed for quite some time in both US and UK. But as the case laws in US and UK show, it is applied differently. As the right in the UK too originally emerged due to concerns about how the police coerced evidence, and how the prosecution too benefited from court rules that (1/2)
    – sfxedit
    May 2, 2023 at 15:10
  • @hszmv allowed similar tactics on the accused to incriminate themselves, it is not at all far-fetched to assume that the political differences in how policing and prosecution is done in the US and UK offer a reasonable explanation to why the application of this right varies. For example, in India, prosecutors are forbidden from being involved in the investigation stage to protect the rights of the accused. That difference is one explanation of why prosecutorial conduct and rights vary between US/UK vs India. Let's also not forget that policing in the US was even worse in the past... (2/2)
    – sfxedit
    May 2, 2023 at 15:22

In the US with 50 different state jurisdictions, the federal government as well as many others such as Native reservations this must come up frequently.

While the U.S. States, Territories, Tribal Lands, and the District of Columbia all have separate sovereignty from the Federal Government, it is rare this issue would come up. Most U.S. crime is prosecuted at the Sub-Federal Level, meaning states or similar entities are responsible for the vast majority of crime in their jurisdictions. Typically, the Federal Government will observe an internal policy known as the Petit Policy, which creates rules for itself that will limit the federal government from prosecuting a crime that a state is prosecuting regardless of outcome at trial, unless certain conditions are met (The most common condition is that some element of the crime was an exclusive federal crime that the states cannot legally prosecute.).

States are only able to prosecute for crimes within their jurisdiction. If Alice is pulled over for driving on a suspended license in Texas, and she's wanted for murder in Kansas, the state of Texas will prosecute her for the suspended license, but they would not have any say in how Kansas prosecutes for the murder. The Federal Government may prosecute for the murder, since they have a similar crime, but the Petit Policy kicks in and they will not prosecute if Kansas does. The Feds have absolutely no suspended license laws (as licensing drivers is a state power) so Alice did not break a law as far as the Federal Prosecutors are concerned, since they have no law on the matter.

If Texas offered Alice immunity to her crimes to testify against Bob, the drug lord she sells for, it is only offering her immunity for the Driving on a suspended license. Thus, only her testimony as it relates to that crime is given any immunity, because Alice is not wanted for Murder in the State of Texas. She would have to cut a deal with Kansas Prosecution.

Edit for your Scenario: She would only be given immunity for crimes in Texas (supposing Bob killed someone while Alice was packing up her latest shipment in a truck.). Alice would likely be charged at worst with Possession with Intent, though offering testimony against a drug kingpin might be juicy enough for to get immunity (or a plea deal, at which point double jeopardy means Texas can't charge her a second time thus she can't plea the 5th... typically a plea can be processed quicker than full blown trial).

Assuming, upon witnessing the murder Alice went to a Texas Law Enforcement Agency and she got a Lawyer OR she was stopped by Texas police at which point the drugs were observed and offered testimony against Bob in exchange for a plea/immunity. Her own lawyer would coach her in answering questions and it's easy for her to say she sells drugs under Bob's orders without testifying to specific location. If pressed by the Prosecuters, Alice's own Lawyer would likely object, since the immunity deal only covers crime in Texas, but the answer of a specific location may incriminate her in another jurisdiction (Kansas and the Federal Government, since she's crossing state lines to deal drugs), which would mean the 5th Amendment is in play. Ultimately, this will be a matter for the trial attorney to decide, but where she sells is not material to witnessing a Murder in the State of Texas. You only need to know that she sells for Bob, which is why she was at the scene of the crime to witness Bob commit the Murder.

Finally, unless Kansas is investigating her OR has a warrent out for her arrest, her testimony that she sells for a drug lord is not evidence that she sells drugs in Kansas (or ever crosses any state lines, for the Feds concerns.) If Alice is stopped in Texas with the contraband, it's unlikely that there is enough proof that she was driving to a state line for either side to use that same evidence against her (since it never left Texas, no crime of Possession with Intent occurred in Kansas... or crossing state lines in for that matter) which makes it difficult to say that falls into something that Kansas or the Feds can prosecute on its own.

  • The scenario I was imagining was that if Alice sold drugs for Bob in Kansas and saw Bob kill someone in Texas. If Alice was to testify as to their relationship in Bobs murder trial in Texas, and received immunity in return for her testimony, could her testimony be used against her in a drug trial in Kansas?
    – User65535
    May 2, 2023 at 12:04
  • @User65535 See my edit for your full response. TL;DR: The Texas prosecutors can ask their questions in a way that.
    – hszmv
    May 2, 2023 at 13:02

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