[mike_hearn]

There's nothing distinctly Tory about Brexit.

1. The Lib Dems also made a promise on an in/out referendum and it was in their 2010 manifesto. You may not recall this because in 2008 Jo Swinson said “the Liberal Democrats would like to have a referendum on the major issue of whether we are in or out of Europe” but by 2016 she was saying she can't forgive Cameron for allowing a vote.

2. Cameron only conceded on allowing a vote due to losing voters to UKIP, a different political party. He clearly didn't want to do it but his hand was forced by the voters.

3. Labour of course committed to and held the original in/out referendum in 1975. They also committed to holding a referendum on the EU Constitution, a promise they backpedalled on after similar referendums were lost in the Netherlands and France. Their 2015 manifesto promised an automatic referendum on any further transfer of powers to the EU.

So all the major UK parties other than the SNP have a history of either promising or holding referendums on the EU. That isn't a surprise because the EU was a major source of constitutional stress and voter unhappiness on all sides of the political spectrum.