Amal Clooney has said she is resigning as the UK's special envoy on media freedom over the Government's "lamentable" suggestion it could violate international law over the Brexit Withdrawal Agreement.

In a letter to the Foreign Secretary Dominic Raab, Mrs Clooney, who is from Gerrards Cross, wrote: "When the Foreign & Commonwealth Office (as it then was) asked me to serve as Special Envoy on Media Freedom, the role was described as one in which I would assist the UK in championing the right to a free press around the world.

"My role was intended to help promote action that governments could take to ensure that existing international obligations relating to media freedom are enforced in accordance with international law. I accepted the role because I believe in the importance of the cause, and appreciate the significant role that the UK has played and can continue to play in promoting the international legal order.

"In these circumstances I have been dismayed to learn that the Government intends to pass legislation - the Internal Market Bill - which would, by the Government's own admission, 'break international law' if enacted.

"I was also concerned to note the position taken by the Government that although it is an 'established principle of international law that a state is obliged to discharge its treaty obligations in good faith', the UK's 'Parliament is sovereign as a matter of domestic law and can pass legislation which is in breach of the UK's Treaty obligations'.

"Although the government has suggested that the violation of international law would be 'specific and limited', it is lamentable for the UK to be speaking of its intention to violate an international treaty signed by the Prime Minister less than a year ago.

"Out of respect for the professional working relationship I have developed with you and your senior colleagues working on human rights, I deferred writing this letter until I had had a chance to discuss this matter with you directly. But having now done so and received no assurance that any change of position is imminent, I have no alternative but to resign from my position."

Mrs Clooney said she was "disappointed" to have to resign because "I have always been proud of the UK's reputation as a champion of the international legal order, and of the culture of fair play for which it is known".

"However, very sadly, it has now become untenable for me, as Special Envoy, to urge other states to respect and enforce international obligations while the UK declares that it does not intend to do so itself.

"As the President of the Bar Council of England and Wales has affirmed, undermining the rule of law that 'this country is built on... will fatally puncture people's faith in our justice system'.

"And it threatens to embolden autocratic regimes that violate international law with devastating consequences all over the world."