Azadeh Assadi and Vahid Saderigh have been providing crucial support to opposition leaders in Tehran from their homes in London, The Daily Telegraph has learnt.

The exiles, who have no chairman or organising committee, take their cue from Iran’s Green Movement which has been the rallying point for an unprecedented challenge to the leadership of the Islamic Republic since the June presidential election.

Government spies were able to compile a list of all those attending a recent opposition meeting at Conway Hall, University of London.

Iranian leaders have consistently blamed British meddling for the eruption of protests after President Mahmoud Ahmadinejad was re-elected in June. David Miliband, the Foreign Secretary at one point dismissed the allegations as “wholly without foundation.”

However, the London-based activists reject the government’s claims. “We were never after revolution but the implementation of the republican democracy promised to the Iranian people 30 years ago,” said Miss Assadi. Kayhan, a newspaper that acts as a conservative mouthpiece, denounced the gathering as an “unwritten coalition of counter revolutionaries” that was spearheading opposition around the world.

It said the use of the green flags, the colour of Islam, masked a hidden agenda. It said: “It looks as though the symbolic colour of these people would be more representative of their spectrum if their flag included the emblem of the freemasons, the Union Jack of Britain, the Star and Stripes of the US and the David of Israel.”

Miss Assadi played a leading role in the 1999 student protests on Iran’s campuses. Like many participants in that movement she suffered harassment and detention before leaving to study in Britain in 2005.

Until a few weeks ago, she had put the turbulent world of protest movements in the past and was studying for articles as a chartered accountant while running the office of a dentist in Hertfordshire.

But within hours of the first result of the June 12 presidential election, she was on the streets outside the Iranian Embassy in Kensington.

“I remember saying to my brother ‘come on, lets go,” she said. “And I am really proud that we in London kept those protests going for 31 days, more than anywhere else. I met so many people who have come together and got organised to give voice to the demands of the Iranian people.”

Mr Saderigh escaped Tehran after spending five years in prison for underground democratic activities. His body is scared from acid burns and other forms of torture. He tours London in a battered Vauxhall with a laptop in the boot to set up meetings and raise funds for the campaign. The pair have supplied followers with green wrist bands and T-shirts to distribute at demonstrations. But the most important aspect of their work to pass messages between supporters under surveillance at home.

“We’re relying on traditional way of Iranians to communicate – word of mouth,” said Mr Saderigh. “We have to use the most basic communication because even text messaging is switched off. One single colour is linking us. In street protests anyone who wears green becomes a member.”