London, Nov 15: Iran’s former top negotiator with the West on Tehran’s nuclear programme has been arrested on charges of spying for Britain.

Hossein Mousavian, who played a key role in Iran's weighed down nuclear negotiations with the West, allegedly passed classified information to the British Embassy in Tehran.

Mousavian is also accused of meeting and communicating with foreign agents and exchanging sensitive information with them.

Mousavian was taken into custody on Monday, shortly after he appeared at a rally next to his close friend and former president Hashemi Rafsanjani, a leading rival to President Mahmoud Ahmadinejad, when he warned that Iran was facing "serious threats, " Daily Mail reported.

It was Mousavian's first major public appearance since being released in May after a brief detention on suspicion of espionage.

Mousavian was a senior member of Iran's negotiating team between 2003 and 2005 under former reformist President Mohammad Khatami.

After the hardline President Mahmoud Ahmadinejad was elected, the negotiating team was removed on accusations of making too many concessions to the West.

Significantly, on Monday, President Ahmadinejad attacked critics of his nuclear policies as "traitors" and accused them of spying for Iran's enemies.

A spokesman for the Foreign Office in London has reportedly declined to comment immediately on Mousavian’s arrest.

However, one official in the Middle East said, Mousavian regularly met European envoys in Tehran from October 2003 to hold negotiations to resolve the nuclear dispute.

"It was normal diplomatic activity in that we sought to find out what the Iranian position was and he conveyed the Iranian position, " one European Envoy was quoted, as saying.

Mousavian is likely to appear before Iran's Revolutionary Courts. The charges carry sentences of up to life in prison.

The latest development will put more pressure on the tense diplomatic relationship between London and Tehran over Iran’s nuclear enrichment programme at a time when the United Nations is considering stepping up sanctions against Iran. (ANI)