GETTY Russia was initially blamed for the cyber attack

FREE now SUBSCRIBE Invalid email Make the most of your money by signing up to our newsletter fornow We will use your email address only for sending you newsletters. Please see our Privacy Notice for details of your data protection rights.

Around 9,000 email accounts, including those belonging to Theresa May and other Cabinet Ministers, were hacked in the 12-hour "sustained and determined" attack June 23. Russia was initially blamed but investigators have traced the source of the hit to the Tehran regime, according to The Times. The House of Commons said it did not comment on security matters. A National Cyber Security Centre spokesman said: "It would be inappropriate to comment further while enquiries are ongoing." It is unclear what the motive for the attack was, but some theories being investigated are “classic cyber espionage” to discover material that could harm UK interests.

The attack could also be that Tehran was seeking information to gain a commercial advantage. Sources described the regime as “highly capable actors in the cyber world”. Another said: “It was the not most sophisticated attack but nor did it need to be. “It is possible they were simply testing their capability.” Downing Street did not comment but a senior British official acknowledged that the revelation had complicated Mrs May’s response to Mr Trump.

The revelations come as Britain and other European powers have been trying to keep the Iran nuclear deal on track after President Donald Trump's refusal to back it. The Prime Minister joined Germany's Angela Merkel and France's Emmanuel Macron to issue a statement insisting preserving the pact. They said it was "in our shared national security interest" and they have called for Washington to "consider the implications" of undermining it. A statement from the UK, France and Germany said the International Atomic Energy Agency has "repeatedly confirmed" Iran's compliance with the terms it signed up to.

Islamic Revolution: Shocking moments depict the horrors of the events Fri, February 10, 2017 The event marks the 38th anniversary of the Islamic revolution, which came ten days after Ayatollah Ruhollah Khomeini's return from his exile in Paris to Iran, toppling the monarchy system and forming the Islamic republic. Play slideshow Getty Images 1 of 19 Demonstrators loot government bureaus and banks as well as liquor shops, cabarets and cinemas during the Revolution in Tehran, 4th November 1978

It said: "We, the leaders of France, Germany and the United Kingdom take note of President Trump's decision not to recertify Iran's compliance with the Joint Comprehensive Plan of Action (JCPA) to Congress and are concerned by the possible implications. "We stand committed to the JCPA and its full implementation by all sides. Preserving the JCPA is in our shared national security interest. "The nuclear deal was the culmination of 13 years of diplomacy and was a major step towards ensuring that Iran's nuclear programme is not diverted for military purposes." Trump accused Tehran of violating the spirit of the landmark 2015 agreement and believes the international community is being naive in its dealings with the regime.

GETTY There are also concerns that Iran was trying to find embarrassing material to blackmail MPs

The President stopped short of ripping up the deal but said without measures to toughen it up "the agreement will be terminated". Shadow foreign secretary Emily Thornberry said it was "high time" the Government challenged Mr Trump on his actions and accused him of “vandalism”. She said: "It is an act of wanton vandalism for Donald Trump to jeopardise the future of that deal today, and to move the goalposts by linking it to important but utterly extraneous issues around Iran's wider activities in the region.

GETTY Emily Thornberry said it was "high time" the Government challenged Mr Trump on his actions