The strange rise of the DUP is heading for its dramatic finale

Why is a party that insists on different laws on abortion and same-sex marriage so inflexible when it comes to complete parity over animal hygiene regulations and customs checks?

Boris Johnson has decided that he will have to shake off the chains of dependence on Arlene Foster’s DUP (Getty)

After a referendum involving 33.5 million people, three and a half years of negotiations and a dramatic last-minute agreement, the fate of Brexit may now lie in the hands of 10 Northern Irish MPs elected by a total of little more than 215,000 voters between them.

The Democratic Unionist Party’s announcement that it will not support Boris Johnson’s deal in parliament may have killed off any hopes he had of fulfilling his promise to take the UK out of the European Union on 31 October.

And it was a graphic demonstration of how the unique circumstances of the UK’s political landscape has elevated a group which previously had little more than regional clout into the “little party that did”.