Boris Johnson is to launch the biggest advertising campaign since the Second World War to get Britain ready for a no-deal Brexit, with an unprecedented marketing blitz on billboards, radio and television.

On Sunday the Prime Minister ordered his ministers to go into overdrive to prepare for a no-deal exit, with daily briefings on progress in the Cabinet Office’s Cobra briefing room – a place normally reserved for co-ordinating responses to national emergencies.

Part of the preparations involve up to £100 million spent on advertising alone in the next three months, government sources said.

It came as it emerged that Liz Truss, the International Trade Secretary, will this week start preliminary work on negotiating a trade deal with the US before the UK leaves the European Union on Thursday, Oct 31.

Ms Truss is due to meet Woody Johnson, the US ambassador to the UK, this week before flying to Washington for talks with Wilbur Ross and Robert Lighthizer, her American counterparts, about the deal later next month.