LONDON: Tony Blair risked his political future when he joined George W. Bush's war on Iraq but as the United States turns on neighbouring Iran, the British prime minister may have less of an appetite to get involved in another Gulf showdown.

The United States, which branded Iran part of the same "axis of evil" as Saddam Hussein's Iraq, has swung its spotlight on Teheran's suspected nuclear weapons programme and alleged sheltering of al-Qaida militants.

Just as he did over Iraq, Blair has ratcheted up his own warnings against Iran. But he has toed a less aggressive line than Washington and anxiously tried to play down talk of a rolling US mission to topple Middle East governments.

"Nobody is threatening military action in respect of Iran," Blair said.

On the eve of the Iraq conflict, the British prime minister survived a seismic Labour rebellion, only to find himself fending off post-war allegations that he exaggerated Saddam's military threat to justify sending troops to battle.

Blair would face a huge challenge making the case for military action while two parliamentary committees probe claims that his staff pressured intelligence services to "sex up" reports on Iraq's alleged weapons of mass destruction.

And he is not facing an exact re-run with Iran, a more formidable nation than Iraq after a decade of United Nations sanctions.

Unlike the case with Baghdad, his government - along with European Union partners - is committed to engagement with Teheran. Britain has strengthened ties with Iran in recent years, while Washington has no diplomatic presence there.

"We have worked very long and hard to have a proper dialogue with the Iranian Government," Blair said.

An escalation of US pressure on Iran could strain London's links with Washington, which form the cornerstone of Blair's foreign policy, said Ali Ansari, an Iran expert at the Royal Institute of International Affairs.

Ansari said there was little sign Blair and Bush were working together to extract maximum concessions from Iran. "The good cop, bad cop game needs a certain agreement to co-ordinate and there just isn't one," he said. "The splits will come as the Americans want to go further and start to talk about military action. That's when Blair, or at least his cabinet and military, will oppose it."

The transatlantic differences over Iran match those over Syria, another Middle East state whose so-called weapons programmes and support for militant groups has attracted Pentagon scrutiny in the wake of Saddam's downfall.

"Britain has a different policy towards the so-called rogue states generally - that engagement is more constructive than brute force," said Middle East analyst Alan George.

Analysts say the possibility of US troops getting bogged down in post-war Iraq and next year's presidential elections in the United States weigh against any major new military action.

But they say the United States could push for air strikes if Iran rejects demands for inspection of its nuclear energy programme.

Agencies via Xinhua