Britain has been "humiliated" by Iran over the hostage crisis - even as President Ahmadinejad promises to release our 15 captives, a leading analyst claimed today.

Robert Bailey, a Middle East specialist, said that Iran had made Britain look "hapless" in front of their Arab neighbours, particularly Iraq.

And he said that Britain had handled the situation badly by refusing to apologise to the Iranians, and questioned why the Royal Marines and sailors were verging on Iranian waters in the first place.

President Ahmadinejad pledged today that he would release the captives as a "gift" to Britain, but only after a lengthy criticism of British foreign policy.

He also repeated allegations that the British sailors and marines had trespassed into Iranian waters.

And he implored Tony Blair not to try the soldiers after they had "admitted" their transgression on Arabic television.

Mr Bailey said: "Tehran has come out of this smelling of roses, while we look hapless.

"In terms of the tabloid press here and the New York Post, Iran are the bad guys. But in terms of the Middle East, Iran and Tehran have come out on top.

"Of course it's not nice to parade people as hostages, but in the wider picture of things we've been humiliated, and there's no escaping it.

"If we hadn't been, the captives will be returning in their uniforms and boats, but that's not going to happen. They will end up in a museum, as an exhibit on 'How we beat the British'."

He said that the instant surrender of the captives had damaged Britain's image in the Middle East, and that Iran had made a point of parading them on Arabic TV channels.

He said: "We've been made to look stupid - 15 people captured, surrendering their guns and admitting their guilt makes us look stupid. It's not exactly the cartoon character of 'Bulldog Britain'. We've lost this round and we look stupid.

"We've lost face, and it's noticeable that all the broadcasts of the captives have been on their Arabic language channels. It's not directed at us. They want to show their Arab neighbours and particularly Iraq that they have humiliated us."

Mr Bailey said that British personnel had no reason to be in the stretch of water in the first place, and claimed that the Government had reacted too aggressively to the capture.

He said: "A better way of approaching it would have been to apologise instead of saying 'Let these people go immediately!' I don't think it's been handled particularly well by us, in my opinion.

"We should have said 'We may have been at fault, and if we were, we apologise, and we'll try and make sure it never happens again'.

"What on Earth are we searching these waters for anyway in such an uncharted area? We're meant to be handing over the whole caboodle to Iraq soon, so what's it all about?

"There's a lot of unanswered questions. It's difficult to know what we were doing there. Who cares about a few Japanese cars being smuggled into Iraq?

"It's arrogance. We think we can operate with impunity and take these kinds of risks. Tehran may be in the right. They are entitled to challenge and stop people in territorial waters. But it could have been diffused in 48 hours."

Mr Bailey said the reason for the apparent release of the captives may not become clear for some time, but said that opposing forces may have been at work within the Iranian power structure.

He said that it was possible the Brits had been captured by the Iranian Revolutionary Guard, but that their release had been secured by others who felt that Britain could prove an important negotiator if relations between Iran and the United States deteriorated further.

Mr Bailey added: "The thing about Iran is that it's got a very labyrinthine power structure, and no one has come to a conclusion about why they were arrested, and why they haven't been released quickly.

"In 2004, about eight British marines in a similar boat were arrested in the same area. They were blindfolded and not treated particularly well, but they were released in about a week.

"This whole episode may be linked to the fact that five Iranian diplomats were arrested in Iraq earlier this year by America, and they have recently been visited.

"There may well be other things happening that we don't know about. American foreign policy is under attack from the US themselves. There's quite a lot going on at the moment.

"I think a lot of other things have been going on beneath the surface in the secret service with America. We are meant to be their closest allies, and we feel that we have an influence in Washington.

"If things go wrong, London could be of great value to Tehran and negotiating with America.

"The leadership is not connected, and the revolutionary guard might have acted on its own in capturing them, and it escalated from there.

"The Iranians want to deflect any notion that they are going to be attacked. There are two American aircraft carriers in the gulf, and there have been reports in the Middle East that they may be planning strikes.

"It's in the interest of the Iranians not to complicate matters. They've made their point."