According to a recent BBC article:

On 27 February 2020, the Court of Appeal ruled the decision to allow the expansion was unlawful because it did not take climate commitments into account.

The judges said that in future, a third runway could go ahead, as long as it fits with the UK's climate policy.

Not surprisingly, Heathrow bosses want to keep alive the plans for the redevelopment and believe that they can.

A spokesman said they were confident an appeal to the Supreme Court "will be successful" and added they would work with the government in overcoming obstacles to the plans.

However given that in the UK parliament holds absolute power, why doesn't the government simply propose a law to overrule the courts? The Conservatives currently hold a comfortable majority in Parliament, so getting the required number of votes should be relatively easy.


4 Answers 4


Chiefly because pundits seem to agree that current government doesn't actually want the Heathrow expansion to proceed. It should be noted that the Government is not pursuing an appeal to the Supreme Court; the case is being pursued privately by Heathrow Airport itself.

The current Prime Minister, then Foreign Secretary, Boris Johnson, was conveniently absent on a trip to Afghanistan for the vote in the House of Commons that approved the third runway in June 2018. This was likely due to his previous commitments to oppose the expansion - he told supporters in his constituency that he would "lie down with you in front of those bulldozers and stop the building, stop the construction of that third runway". Because of collective Cabinet responsibility, he would have been forced to resign if he voted against the proposals.

The legal case was brought by Sadiq Khan, the Mayor of London in response to the decision, and argued that the Government, in particular the Transport Secretary, Chris Grayling, had not considered its commitments to the Paris Climate Agreement. Because this was upheld by the Court of Appeal, the Government must now show that the expansion is consistent with the commitments made - and be able to satisfy the courts of that - or repeal the act that formalised the UK's agreement to the climate accord. This would be considered quite an embarrassing option, considering Johnson's public criticism of President Trump, when the US exited the agreement in 2019.

In conclusion, then, of course it is within the ability of the UK Government to legislate to allow the third runway, however it is questionable if this is firstly, proportionate - it would require at minimum de facto exiting the Paris Climate Agreement, or secondly - what the Government actually wants to do.

  • 1
    The Paris Climate Agreement is not specific; the UK government has the freedom to choose implementation measures. The problem with Heathrow is a lack of compensation measures elsewhere, which would raise the costs even further. But that's a financial argument.
    – MSalters
    Mar 9, 2020 at 13:42

As is true most everywhere, the answer is likely political cost.

Courts are not inherently political bodies, and are thus insulated somewhat from the political process. There's no political cost to the UK courts ruling it cannot happen.

The same is not true for Parliament. While this is not a major case, there doesn't appear to be any political will to overturn it at present and, most importantly, the Prime Minister is against it. Boris Johnson promptly abandoned the plan after the ruling (emphasis mine)

The judgment – that the third runway is “unlawful” by failing to take into account the UK’s climate change commitments – now looks likely to give Boris Johnson a convenient exit route from the scheme.

Asked whether it was the government’s intention to appeal against the decision​, the prime minister’s spokesman replied: “It is not.”

Heathrow management is handling the appeal, but it's unclear how far it will go if Parliament leadership is against it.

  • 1
    Well, there is a political cost to the courts ruling you can't do something. It makes you look incompetent. But once it's happened there are obviously a lot more costs involved in doing something specific about it.
    – Jontia
    Mar 18, 2020 at 14:44

The quote you have provided is from 'Heathrow bosses' not members of the current government. The government will not be appealing the decision.

In fact, the court blocking the runway is a major let off for Boris Johnson who in 2015 vowed to;

“lie down in front of those bulldozers and stop the construction”.

That aside there are a number of reasons for appealing over passing a new law.

  1. Being seen to follow the Paris agreement, appealing (and winning) would keep the UK government's green credentials intact and make this judicial over reach, not government backing money over the planet.
  2. Ammunition for review of role of the courts. The 2019 manifesto promised this review and big cases being overturned lends it more respectability than losing big cases, like the prorogue issues that makes it look like sour grapes.
  3. Avoid rebellion on a vote. While the conservatives have a comfortable majority, expansion of Heathrow has been deeply unpopular with the local MPs rebellion even if not sufficient to lose the vote in this instance risks making MPs feel empowered to vote their minds on other issues.

Adding to the other answers, introducing legislation that provides advantage to a single private organisation is likely to be seen as improper. It also has the potential for other private organisations asking for the Government to step in and introduce legal exclusions for their plans.

As an example, where I live, major developments are required to undergo review by a planning tribunal. One development proposal was rejected (for environmental and uncertainty over its financial stability) the Government stepped in and overrode the tribunal and public opinion.

2 years later, after all the licences, etc were issued, the development was halted because the company couldn't obtain finance as the company had already been generating a loss for the last 15 years. The company no longer exists and liquidators still have control over the site 10 years later.

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