Arlene Foster, leader of the DUP, right, and Diane Dodds, a DUP member, met the European Union's chief Brexit negotiator, Michel Barnier, in Brussels on Tuesday

Theresa May was warned by the DUP that it would be prepared to bring down her government if she signed up to a compromise with Brussels to solve the Irish border question next week.

In an explicit threat to the British prime minister before a critical five days of negotiations in Brussels, the party threatened to withdraw support for the UK budget this month unless it was happy with the final deal. Last night the DUP underlined its point by abstaining in a Commons vote in which it would normally have been expected to support the government.

The move, which involved a Labour amendment to the agriculture bill, was co-ordinated with Tory Brexiteers, The Times understands. It was designed to put maximum pressure on Mrs