Boris Johnson has said he continues to support the Iran nuclear deal after Israel claimed Tehran had covered up its weapons programme.
Israel said it had documents showing that Tehran covered up the programme before signing the deal with the international community in 2015.
Donald Trump has warned he could walk away from the deal and Israel Prime Minister Benjamin Netanyahu urged him to do so, claiming that the material showed Iran cannot be trusted.
“Iran lied, big time,” Mr Netanyahu said.
He based his presentation on some 55,000 pages of documents and 183 CDs of secret information Israeli Mossad operatives obtained from a Tehran facility.
The US president has signalled he will pull out of the agreement by May 12 unless it is revised.
But the UK continued to support the deal and insisted that the inspection regime placed on Iran as part of the Joint Comprehensive Plan of Action (JCPOA) agreement was designed to ensure Tehran’s compliance.
The Foreign Secretary said: “The Israeli prime minister’s presentation on Iran’s past research into nuclear weapons technology underlines the importance of keeping the Iran nuclear deal’s constraints on Tehran’s nuclear ambitions.
Israeli PMâs speech on Iranâs past nuclear weapons research shows why we need Iran Nuclear deal. Iran deal based not on trust but verification, allowing @iaeaorg unprecedented access. Need to keep deal & build on it to take account of US & alliesâ concerns https://t.co/To50dEs3zM— Boris Johnson (@BorisJohnson) May 1, 2018
“The Iran nuclear deal is not based on trust about Iran’s intentions; rather it is based on tough verification, including measures that allow inspectors from the International Atomic Energy Agency unprecedented access to Iran’s nuclear programme.
“The fact that Iran conducted sensitive research in secret until 2003 shows why we need the intrusive inspections allowed by the Iran nuclear deal today.
“The verification provisions in the Iran nuclear deal would make it harder for Iran to restart any such research.
“That is another good reason for keeping the deal while building on it in order to take account of the legitimate concerns of the US and our other allies.”
Downing Street also backed the terms of the Iran deal.
The Prime Minister’s official spokesman said: “We have never been naive about Iran and its nuclear intentions, that is why the International Atomic Energy Agency inspection regime agreed as part of the Iran nuclear deal is one of the most extensive and robust in the history of international nuclear accords.
“It remains a vitally important way of independently verifying that Iran is adhering to the deal that Iran’s nuclear programme is exclusively peaceful.”