In case you hadn't noticed, within the last 20 years the UK made an enormous constitutional change by leaving the EU.
Made by the people rather than the politicians- the mainline politicians all thought it would/wanted it to fail- they just thought they’d get a boost from catering to a disaffected minority.
That is the one change, and it hasn't resulted in the thing people actually were voting for (but couldn't): less immigration. Because the state says we must just import 750k people a year, so that's that.