Britain faces shortages of fuel, food and medicine, a three-month meltdown at its ports, a hard border with Ireland and rising costs in social care in the event of a no-deal Brexit, according to an unprecedented leak of government documents that lay bare the gaps in contingency planning.

The documents, which set out the most likely aftershocks of a no-deal Brexit rather than worst-case scenarios, have emerged as the UK looks increasingly likely to crash out of the EU without a deal.

Compiled this month by the Cabinet Office under the codename Operation Yellowhammer, the dossier offers a rare glimpse into the covert planning being carried out by the government to avert a catastrophic collapse in the nation’s infrastructure.

‘A lot of the negativity about a no-deal Brexit has been wildly overdone’ — Boris Johnson on July 2

The file, marked “official-sensitive” —