Ministers are to stage emergency exercises at the border next month to see if ports and airports could cope with a no-deal Brexit. The plans, which will test Border Force computer systems and staff, could see people with fake passports or lorries of sheep used to check preparations. “We’ll be testing the border from end to end,” a cabinet minister said.

Ministers were informed of the plans at a no-deal Brexit cabinet meeting last week, when David Lidington, Theresa May’s deputy, brokered a compromise on preparations for leaving the EU. At his suggestion, ministers agreed that no-deal planning will be the “principal operational focus” of the government for the foreseeable future — with other manifesto commitments ditched.

Lidington’s intervention provided a middle ground between ministers