In reply to cragtaff:
> We had a referendum on joining the Common Market..., why then should we not have one to leave it?
That's a good point, although we have had a referendum to leave the E.U., we haven't addressed the issue of whether we should leave the European Economic Area (EEA - formerly the Single Market - formerly the Common Market) so we need a second referendum to find out what the people want.
> If it is an issue that has never been part of a political party's election manifesto surely they have a duty to consult the electorate on that issue?
That's another good point, since the 2015 Conservative manifest said
"We want to expand the Single Market, breaking down the remaining barriers to trade and ensuring that new sectors are opened up to British firms." then the Government doesn't have a mandate to take us out of the EEA, the only way to legitimise such an action before the next General Election would be to hold another referendum.
Thank you for helping me clarify that.