Alan Renwick and Meg Russell take a long, cool look at some of the difficult issues that surround a second referendum: Key questions
They reckon that it would take at least 22 weeks to hold a referendum which would require an Article 50 extension. There are tricky issues in relation to next May's European Parliament elections.
Probably the most difficult issue is how a referendum question should be structured. They state, 'There is no perfect system that would allow all voters to express their preferences and guarantees an unambiguous result.'