The main challenger in Iran’s looming presidential race yesterday sent a message of conciliation to President Obama and the West, setting out a starkly different approach to the provocative policies of President Mahmoud Ahmadinejad.

Mir Hossein Musavi, a former prime minister and now the main reformist candidate for president, told The Times last night that he would be prepared to meet Mr Obama if relations between the two countries improved and that he intended to pursue a very different style in his dealings with the outside world.

Speaking on the margins of an election rally in northern Tehran, the grey-haired veteran politician, seemed to lack the populist appeal and fiery rhetoric of his opponent, who is facing re-election on June 12.

Nevertheless, he has won support from powerful reformist figures, like the former president Mohammad Khatami, and his campaign headquarters in central Tehran is bustling with young volunteers and clearly well-funded.

Asked if he would be prepared to meet Mr Obama, he said: “Yes I would meet him if things go according to plan.” He insisted that it was not up to the president to take strategic foreign policy decisions, which under Iran’s constitution are decided by the national security council.

He did, however, pledge that were he elected president he would “change tactics” even if the same strategy remained in place. By that he was referring to what many reformist Iranians regard as the counter-productive public pronouncements of Mr Ahmadinejad, whose speech against Israel this week at a United Nations racism conference in Geneva led to a boycott by 10 countries and a walk-out by 30 more .

Mr Mousavi, 67 who is best remembered in Iran for leading the country’s government during the bloody Iran-Iraq war in the 1980s, went out of his way to praise Mr Obama’s speech to the Iranian people last month . Many hardliners in Iran, including the Supreme Leader Ayatollah Khamenei, have denounced Mr Obama’s unprecedented gesture of reconciliation as a trick and have accused the US leader of not making any concrete policy changes.

Mr Mousavi acknowledged that Iran was cautious because of its “bitter experience” with America over 30 years of hostility. But he added: “My own opinion is that what President Obama has done is a step forward.” He said that if he became president he would try to build on that.

The other candidate in the presidential race, Mehdi Karoubi, another reformist, also told The Times that he would seek to improve relations with the West and undo some of the damage done under Mr Ahmadinejad’s four-year presidency.

Neither challengers, however, are prepared to freeze Iran’s controversial nuclear programme, which many regard as the most potentially explosive issue in the country today.

While the two reformers have begun their campaigns across Iran, Mr Ahmadinejad remains the firm favourite to win in June’s election. Most Iranian presidents have served two terms, he has the considerable resources of the government at his disposal, including support from the powerful Revolutionary Guards and Basij paramilitary force. Above all he seems to have the trust and tacit backing of the Supreme Leader, who is supposed to remain above politics but whose hardline views are thought to coincide closely with the president’s.

Hossein Shariatmadari, an advisor to the Supreme Leader and the head of Iran’s influential Kayhan newspaper group, gave a strong endorsement to Mr Ahmadinejad. He said that the president was very popular with ordinary Iranians, lived a simple and decent life and had stood up to “US aggression”.

Some Iranian voters on the street seemed less convinced.

Ibrahim, a retired government official who lives in Mr Ahmadinejad’s own Tehran neighbourhood of Narmak, said that he had voted for the president in the last election but this time would change his allegiance to Mr Mousavi.

“Ahmadinejad did ok but we are now entering a period when we need calm and a steady hand. I worked for Mousavi and I know him to be a decent man. He is the person we need to deal with Obama,” he said.

Mehdi, a retired worker who also lived in the same area, said he would not be voting at all because Iran’s electoral system was undemocratic.

However, Mahmoud, a pilgrim visiting the shrine of the late Iranian leader Ayatollah Khomeini in southern Tehran, said that he and many like him would remain loyal to Mr Ahmadinejad in the election.

“I will vote for Ahmadinejad. He has done a lot for this country and me in particular. Four years is not enough he needs another term to complete his work,” he said.

Some 46 million Iranians are eligible to vote, but on past experience only about half turn out to cast their ballot. In the last election, Mr Ahmadinejad managed to secure around 13 million votes, many from the well-organised hardline revolutionary institutions. He is hoping to get them out again.

However, some of his support base has eroded. The bazaari merchant class have grown disaffected with his economic policies. Other Iranians are concerned that his aggressive style will lead Iran into new conflict with America and miss the opportunity for reconciliation offered by the arrival of Mr Obama in the White House.

Western diplomats warn that while the election may only be a few weeks away the race could change at the last minute if new candidates come forward before the May 5 registration deadline. That could weaken either the conservative or reformist vote. Mr Ahmadinejad knows only too well that if the election goes into a second round he could be vulnerable. That is exactly how he defeated the favourite in the last elections.

“It is still far too early to tell which way this is going,” said one diplomat.

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