A Jewish charity has called on the Prime Minister to abandon plans to withdraw the UK from the European Convention on Human Rights.

In a letter to Theresa May, human rights group René Cassin urged her not to opt out of the International treaty, which was signed in 1950 by 47 European nations as a response to the atrocities committed by the Nazis.

The charity said it was “surprised” by the government’s plan.

It told Mrs May: “We believe that turning our back on this essential international agreement runs counter to your vision of a ‘Global Britain’ and will diminish this country’s standing in the world.

“Perhaps more worryingly, it will send a message to less enlightened regimes that Britain does not value an internationalist approach to human rights violations.”

The charity pointed out that Mrs May previously expressed support for conventions such as the ECHR, when she was Home Secretary.

It quoted the Prime Minster’s comment in a speech in April, when she said: “Looking back at history and not very distant history at that we know what a world without international, multilateral institutions looks like. 

“The United Nations may be a flawed organisation but nobody should want an end to a rules-based international system.”

The charity wrote: “As a Jewish human rights organisation, your words have particular resonance.

“Last week, Holocaust Memorial Day remembered the horrors committed by the Nazis in a world that had no effective political or legal response to totalitarianism.

“Determined never again to allow such inhumanity, the civilised nations moved quickly to establish the United Nations and that first great proclamation of basic, global, human values – the Universal Declaration of Human Rights.

“It is from the history of this landmark document that we derive our name – René Cassin, a French-Jewish lawyer and later Nobel Laureate, was one of the co-authors of the UDHR.”

Mia Hasenson-Gross, director of René Cassin, said: “The ECHR is both British and Conservative in origin – it was advocated by Winston Churchill and was drafted by former Conservative Home Secretary, David Maxwell-Fyfe.

“Just as Churchill saw the ECHR as essential in upholding European freedoms threatened by Soviet communism, so today the Convention is a vital counterweight to an increasingly authoritarian Russia.”

Speaking in the commons last week, David Jones, Minister of State at the Department for Exiting the European Union, said the government had no plans to withdraw from the ECHR.

He said: “We have made clear commitments to protect workers’ rights, and will ensure that they keep pace with the changing labour market.

“Let me be as clear as it is possible to be: all the workers’ rights that are enjoyed under EU legislation will be preserved by the great repeal Bill and brought across into UK law.

“Let me also say that we have no plans to withdraw from the ECHR.”

The charity said it understood Mr Jones comments to mean the government has “no plans to bring legislation in this Parliament,” but added, “we are sure it will be mooted as part of a Conservative 2020 election manifesto pledge.

“Theresa May has raised it twice in the last 12 months.”