A leading human rights lawyer has warned a no-deal Brexit would be be illegal because of the “real and immediate risk to life”.

Jonathan Cooper, who was awarded an OBE for his work in 2007, says the government would be knowingly putting the British public in danger if the UK crashes out of the EU without an agreement.

Citing threats ranging from a shortage of medicines to a breakdown in law and order, he argues the result will be unlawful under the Human Rights Act and the international human rights treaty obligations.

“As a matter of human rights law, as well as the common law, the UK Government cannot deliberately expose people to policies that risk a loss of life,” he argues in an article for The Independent.

“The fact that a no-deal Brexit will mean deaths that would not have occurred otherwise, demands that the UK Government cannot contemplate no deal.

“The Government knows that there is a real and immediate risk to life by pursuing no deal. As a matter of the UK’s constitutional framework, no deal is simply off the table. No deal breaks the law.”

Mr Cooper, a member of Doughty Street Chambers, says that litigation to stop a no-deal Brexit will be “inevitable” and cases may end up before the European Court of Human Rights.

“The prospect of British cancer patients standing before the European Court simply pleading to stay alive and to put a no-deal Brexit on hold will be the ultimate indignity for Theresa May’s Brexit strategy,” he adds.

“Worse still for the prime minister is that, in the event of no deal, investigations into the loss of life under these circumstances will be carried out in public and responsibility for deaths will be attributed.”

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He also claims that the UK could be held to account at the UN and before the European Court of Human Rights – even if an act of parliament was passed mandating a no-deal Brexit.

“Human rights laws would not prevent Brexit, but they do require a human rights-compliant Brexit,” he writes.

The warning came as the government began testing its contingency plans to ease congestion on roads to Dover in the event of a no-deal Brexit.