Brexit’s backstop blues

Omnipresent and elusive, why has the Irish backstop been so controversial? Peter Geoghegan investigates

A pro-EU group rallies outside the Houses of Parliament ahead of Tuesday’s key voteGetty

In a dark irony, the main cause of prime minister Theresa May’s defeat in the House of Commons last week was an issue almost completely ignored during the Brexit referendum: Britain’s border with Ireland. On Tuesday night, a succession of Conservative MPs adduced the benighted ‘Irish backstop’ as the reason for voting against their own government.

The backstop is strongly supported by the European Union - and the Irish government - but May’s ...