Have an English Tory Prime Minister who reminds everyone of Margaret Thatcher say they can't do it:
Theresa May has moved to block a new Scottish independence referendum by saying "now is not the time" for another vote.
The Prime Minister said a repeat of the 2014 referendum was not appropriate because the country was already going through a huge change in terms of Brexit, and that Scottish people needed a fuller picture before taking any decision on the future.
But her move to block another vote for now creates an intense political stand-off with SNP leader Nicola Sturgeon, who will next week ask Scottish MSPs to approve her plans for a second referendum.
And that is that, I think. May can fulminate all she wants, but by making it clearly an issue of liberal Scotland vs Tory London, and claiming to have a veto on the aspirations of the Scottish people, she's basicly ensured that when a referendum happens, London will lose it.