Theresa May runs into trouble with her Northern Irish allies

AS IF REVOLT on both wings of her own Conservatives were not enough, Theresa May faces rebellion from the Northern Irish party that props up her government. Because the prime minister lost her majority in the election she unwisely called in June 2017, she was forced into a “confidence and supply” agreement with the Democratic Unionist Party. The DUP’s ten MPs promised to vote with the government on confidence matters, Brexit and the budget in exchange for a bung of £1bn ($1.3bn) extra spending in the province.

The deal was widely criticised. A former Treasury permanent secretary noted that the DUP had “previous” when it came to extracting bribes from Westminster. Until two weeks ago the party was at least reliably delivering its votes for Mrs May. Since she unveiled her Brexit deal, however, that reliability has come into question. This week the party exerted its power by...