Until the 1973 Northern Ireland referendum they generally were seen as unconstitutional throughout our history. Thatcher famously agreed with Atlee that referenda were a device of dictators and demagogues[0].

There is nothing to prevent any government, or any future government going against a referendum result. Parliamentary sovereignty means no restriction can be placed on any future administration changing the law.

[0] https://www.economist.com/special-report/2015/10/15/herding-...