Britain would be hit with shortages of medicine, fuel and food within a fortnight if the UK tries to leave the European Union without a deal, according to a Doomsday Brexit scenario drawn up by senior civil servants for David Davis.

Whitehall has begun contingency planning for the port of Dover to collapse "on day one" if Britain crashes out of the EU, leading to critical shortages of supplies.

Last month officials in Davis's Brexit department and the departments of health and transport drew up scenarios for a no-deal Brexit -- a mild one, a severe one and one dubbed "Armageddon".

A source said: "In the second scenario, not even the worst, the port of Dover will collapse on day one. The supermarkets in Cornwall and Scotland will run out of food within a couple of days, and hospitals will run out of medicines within two weeks."

Officials would have to charter aircraft, or use the RAF to ferry supplies to the furthest corners of the UK. "You would have to medevac medicine into Britain, and at the end of week two we would be running out of petrol as well," the source said.

Concern about chaos at Dover was behind a decision by Highways England to announce plans last month to build "one or more lorry holding areas" in Kent "to reduce the congestion caused by cross-Channel disruption".

It is understood that the papers were prepared for the so-called Inter-Ministerial Group on Preparedness, which meets weekly when parliament is sitting. One official said the scenarios are so explosive they have only been shared with a handful of ministers and are "locked in a safe".