How central are referendums to the UK constitution?

Question

I can't remember the link, but someone on Quora typed

Referendums are now a central part of the UK constitution. Voters in the UK have spoken, and they will speak again.

1. How true is this?

2. What official document or law proves if an Act of Parliament doesn't require a referendum, then a referendum isn't legally required? Bradley, Ewing. Constitutional and Administrative Law (2018 17 ed), pages 8,9, prove that some referenda are legally required. But what extent?

There are some notable exceptions to the lack of legal obligation for a referendum, neither of which have yet been triggered. The Northern Ireland Act 1998, s 1, has the effect that the status of the province as part of the United Kingdom cannot be altered without a ‘poll’ held for that purpose providing the consent of the majority of the people of Northern Ireland to a change in that status. Various provisions of the European Union Act 2011 would have required a referendum to be held in the event of certain types of further power being given to the EU; that legislation is of course shortly to be defunct. By amendments brought about in the Scotland Act 2016 and the Wales Act 2017, the Scottish Parliament and National Assembly for Wales (and the respective devolved governments) are now statutorily declared to be permanent and cannot be abolished save on the basis of a referendum result in the relevant territory in support of such a step: s 63A(3) of the Scotland Act 1998 (as amended) and s A1(3) of the Government of Wales Act 2006 (as amended).

Public Law: Text, Cases, and Materials (2019, 4^th edition). Page 156.

      In this context, compare the decision in R (on the application of Wheeler) v Office of the Prime Minister,50 in which the courts rejected Wheeler’s argument that the government’s failure to hold a referendum on the Lisbon Treaty was unlawful because it was in breach of a legitimate expectation that a referendum would be held. The challenge failed, not because the claimant lacked standing, but because the decision to hold a referendum was held to lie so deeply in the political field that the court should not enter.51

Answer 1

Q1. I'm sure there will be another referendum some unknown day in the future, but that hardly makes referendums "a central part of the UK constitution". I'm unaware of any specific plans for any referendums to be held in the near future. The claim seems like a matter of opinion, instead of a matter of law, constitutional theory on solid footing or historical fact. Indeed some politicians viewed referendums as alien to our constitution.

We've only had three nationwide referendums in the UK: the 1975 European Communities membership referendum, the 2011 Alternative Vote referendum and the 2016 European Union membership referendum.

Since the 70s we've had eleven regional referendums, all related to devolution except for the Scottish independence referendum, which was the most recently held in 2014.

Switzerland springs to mind as a country where referendums are "a central part of the constitution".

Q2. We don't need a law or official document that says if "an Act of Parliament of doesn't require a referendum, then a referendum isn't legally required" - if the law doesn't say something is required then it isn't required. Indeed for a referendum to be held and something to happen depending on the result there must be law to provide for it. There is no law providing for national referendums generally - which is another piece of evidence that referendums are not "a central part of the UK constitution".

Of course if a law says a referendum must be held then a referendum must be held unless the law is changed.