The question is raised again by the latest row with the EU – this time over the UK’s involvement in the Galileo space programme.
The Scottish people don’t want another independence referendum - and an abstract legal battle is unlikely to change that.
Northern Ireland Secretary Karen Bradley maintained there would be no new physical infrastructure, no customs union and no sea border - but didn't explain how the Irish frontier will be kept open.
The reality is far from a jobs paradise triggered by the referendum.
The Labour leader embarrassed Theresa May as he asked: “If the Prime Minister can't even convince her own cabinet on Brexit, how can she convince 27 other EU countries?”
Public opinion in Northern Ireland appears to be moving towards the collapse of the union.
Paul Mason should, in general, be praising them, not seeking to bury them.
So much for soft Brexit.
Britain is squandering one of its few remaining assets in the negotiations.
The watchdog has a problem – but it’s one of weakness rather than influence.
The I-Didn’t-Do-It boy strikes again.