Three of Iran’s most prominent opposition leaders flagrantly courted arrest yesterday by denouncing President Ahmadinejad’s Government as illegitimate, one day after the regime said that it would tolerate no more challenges to the election result.

Mir Hossein Mousavi, the former Prime Minister who lost the election, said that the suppression of dissent was tantamount to a coup. “It’s not yet too late,” he declared on his website. “It is our historical responsibility to continue our protests to defend the rights of the people . . . and prevent the blood spilt by hundreds of thousands of martyrs from leading to a police state.”

Ayatollah Mohammed Khatami, 65, a popular former President, accused the regime of mounting a “velvet revolution against the people and democracy” and called the security crackdown “poisonous”.

Mehdi Karroubi, 72, another defeated presidential candidate, said that “visible and invisible forces blocked any change in the executive power”. He added: “I will continue the fight under any circumstances and using every means.” The regime responded by shutting down his newspaper.

One Iranian analyst expressed astonishment at their audacity. “It looks like they’re trying to become living martyrs,” he said. “At the very least they will be put under house arrest. At worst they will be taken to jail and charged with threatening national security.” The regime might hesitate to lock them up because of the prospect of hundreds of thousands of supporters taking to the streets. “The only question is how big the demonstrations would be and how long the people could fight the might of a military state,” the analyst said.

Mr Mousavi, 67, is living at home with his family in Tehran, with security and intelligence agents watching his every move. They have arrested most of his inner circle and made it progressively harder for him to communicate with his followers.

Since Tuesday, when Iran’s Guardian Council declared that a partial recount had confirmed Mr Ahmadinejad’s disputed re-election, hardliners have all but accused Mr Mousavi of treason. Ayatollah Ahmad Khatami, a hardline cleric close to the regime, called him “anti-revolutionary”. The Basij — the regime’s volunteer militia — sent Iran’s chief prosecutor a letter accusing him of nine offences including threatening national security.

Mr Mousavi’s statement said that he was forming a political group to defend citizens’ rights and votes, which suggested that he is preparing a campaign of resistance against Mr Ahmadinejad and his patron, Ayatollah Ali Khamenei, the Supreme Leader.

He still has powerful supporters including two former presidents, Mr Khatami and Ali Akbar Hashemi Rafsanjani, Ali Larijani, the parliamentary speaker, Mohammed Baqer Qalibaf, the Mayor of Tehran, and several leading clerics. Mr Ahmadinejad’s fiscal profligacy means that Iran faces huge economic problems that could eat into his support over the coming months.

Forced from the streets by the security forces, Mr Mousavi’s supporters are also preparing a campaign of civil disobedience. They are talking of strikes, boycotting goods advertised in the state-controlled media, moving money out of government-controlled banks and giving money directly to the needy instead of government-controlled charities.

Analysts say that anger will grow and could erupt at football matches, prayer meetings or anywhere that large numbers gather. They say that opposition supporters will go underground and stage lightning demonstrations. They also expect some elements to start launching violent attacks on government targets.

In a possible sign of the regime’s anxiety Mr Ahmadinejad abruptly cancelled a visit to Libya for an African Union summit yesterday.

The regime appeared to have released two more of the nine Iranians working for the British Embassy in Tehran who were arrested last weekend. One or two are still in custody.

Iran’s police chief, Esmaeil Ahmadi-Moghaddam, said that the authorities were seeking Arash Hejazi, the doctor who tried to save the life of Neda Soltan who was shot dead during a demonstration. Dr Hejazi fled to Britain last week and told The Times how Miss Soltan had been shot by a Basiji. Mr Ahmadi-Moghaddam accused him of encouraging Western media hype.

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