Activists opposing the nuclear deal between Iran and western powers have delivered a letter outlining their objections to 10 Downing Street.

After a demonstration in Whitehall on Sunday attended by more than 30 supporters, pro-Israel grassroots group Campaign For Truth (C4T) handed over the message, which compared the agreement to appeasement of the Nazis.

The letter addressed to Mr Cameron said: “Many of us can recall the result of the last piece of paper signed in the vain hope of ‘peace for our time’, the ashes of our relatives fertilising the green forests of Europe as we vowed ‘never again’.”

The group faced opposition from Jewish anti-Zionists Neturei Karta, who mounted a counter-protest with members waving Iran and Palestinian flags.

The counter-protesters, whose action had not been approved by the authorities, reportedly shouted “Israel hell” at C4T members before being removed by police after 20 minutes.

Sharon Klaff, who founded C4T, said: “Our message is not to have a row with anybody. Our message is very clear: we are asking David Cameron not to allow the Iran deal.

“It's a deal which doesn’t view Iran in terms of human rights in relation to Israel, which doesn’t take into account Iran recognising the state of Israel instead of calling for its destruction. It's hoping, not demanding.”

The group, which campaigned against the neo-Nazi rally planned for Golders Green earlier this month, read out a message of support sent from a former commander of British forces in Afghanistan.

Colonel Richard Kemp wrote that the Iranian regime was a “fascist, imperialist, totalitarian, murderous dictatorship” and said the deal “makes war more likely”.