Britain’s diplomatic relations with Iran deteriorated further yesterday when Tehran’s former top nuclear negotiator was charged with spying for Britain.

Hossein Mousavian, who was the main nuclear negotiator under President Khatami, is accused of passing classified material to the British Embassy in Tehran.

“He has been informed of the charges that he has given the British Embassy information contrary to the security of the country,” said Gholam Hossein Mohseni Ejeie, Iran’s Intelligence Minister. “From the viewpoint of the Intelligence Ministry, he is a criminal.”

Mr Mousavian was first arrested in May and spent ten days in prison on unspecified charges of espionage before being released on bail.

Diplomats said that the charges brought against Mr Mousavian were the result of domestic politics.

Geoffrey Adams, the British Ambassador to Tehran, was not summoned to the Iranian Foreign Ministry to discuss the charges. Diplomatic sources said that there had been no discussions with the Iranian authorities about any spying claims.

One source said: “We’re not treating these allegations with any seriousness.” There is no suggestion that Mr Mousavian is accused of being in cahoots with British intelligence officers.

Mr Mousavian left the Government when President Ahmadinejad was elected but remained an ally of the Iranian leader’s most powerful rivals, former presidents Khatami and Rafsanjani. Both have accused Mr Ahmadinejad of endangering the Islamic Republic with his confrontational rhetoric on the nuclear issue.

The charges against Mr Mousavian will be preceived as a challenge to Mr Rafsanjani, a pragmatic conservative who believes in accommodation with the West.

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