The Government reacted furiously last night to the televised “confessions” of two more British servicemen captured by Iran’s Revolutionary Guard ten days ago and paraded on state-owned channels.

Al-Alam television, an Arabic-language station, and two other channels broadcasting in Farsi aired clips of the British servicemen describing their arrest, and claimed that they had “confessed” to trespassing in Iranian waters.

Lieutenant Felix Carman of the Royal Navy and Royal Marine Captain Chris Air both appeared to be in good health as they were shown in heavily edited footage, which was billed as a prelude to more detailed “confessions”.

“It is unacceptable for these pictures to be shown,” a spokeswoman for the Foreign and Commonwealth Office said.

Michael Moore, the Liberal Democrat foreign affairs spokesman, described the broadcast as “crude and cynical propaganda”. Last week the Iranian authorities released footage of two other service personnel, Faye Turney and Nathan Summers, who were also said to have “confessed” to trespassing into Iranian waters.

Lieutenant Carman and Captain Air were shown in separate footage in front of a large nautical map, apparently of the northern Gulf, where the 15 sailors and Marines were seized during patrol.

The two officers talked into the camera as they pointed at the map using a pen, explaining the location of their boat.

Although the newsreader claimed that both had “confessed” to trespassing into Iranian waters, the transcript showed that Captain Air made no admissions, using the word “apparently” in his description of where they were detained.

Gesturing at the map, Captain Air described the events of March 23, saying: “At approximately 10 o’clock in the morning we were seized, apparently at this point here from their maps and the GPS they’ve shown us, which is inside Iranian territorial waters.”

The words “the point where military boats were captured” were handwritten in red pen on the map. Although the men looked well, a body language expert said that they exhibited signs of nervous behaviour. Robert Phipps said that they were using “high hand barriers” with their pens.

“They’re both holding the pen between both hands, which you don’t need to with a pen, and they are holding it towards their stomachs.

“Any form of barrier you put up, is a barrier against anything that’s in front of you. The higher up the body you hold something the more protective you’re being. One of them also appears to be clicking the pen, which is another sign of nervous activity.”

The former SAS soldier Andy McNab told Sky News that he thought they were “just doing their best to get by”. He said: “They are intelligent people, they understand the situation, they understand they are caught in the middle on a political situation.”

After a weekend when London and Tehran had hinted that they were trying to find a diplomatic solution and confirmed that they were in direct contact, the new footage raised fears that the row could scupper negotiations.

The volatile atmosphere complicated efforts on both sides to reach what Des Browne, the Defence Secretary, said was Britain’s aim of a peaceful settlement. The two sides have exchanged diplomatic notes, which raised hopes of a negotiated agreement that might include a British pledge never to enter Iranian waters without permission.

“We are anxious that the matter be resolved as quickly as possible and that it be resolved through diplomatic means,” Mr Browne told the BBC. “We are bending every effort to that.”

But the private diplomacy is being undermined by the public rhetoric. On Saturday President Ahmadinejad complained that Britain was trying to turn a bilateral dispute into an international problem.

“The British Government, instead of apologising and expressing regret over the action taken, started to claim that we are in their debt and shouted in different international councils,” he said. “But this is not the legal and logical way for this issue.”

Britain’s allies in Europe and America are rallying round. Angela Merkel, the Chancellor of Germany, which holds the presidency of the European Union, said in a speech at the Hebrew University in Jerusalem: “We demand the release of the 15 soldiers and we are standing by Britain’s side.”

Ségolène Royal, the Socialist candidate for the French presidency, suggested that Europe should impose sanctions.

— A British soldier has died after being hit by small-arms fire while on patrol in Basra. An army spokeswoman said that the soldier from 2nd Battalion, the Duke of Lancaster’s Regiment, died of a gunshot wound while on a patrol in the Ashar area of the city.

We were seized, apparently at this point here from their maps and the GPS they’ve shown us, which is inside Iranian territorial waters. So far we have been treated very well by all the people here”

What they said

"We were seized, apparently at this point here from their maps and the GPS they’ve shown us, which is inside Iranian territorial waters. So far we have been treated very well by all the people here”
Captain Chris Air

"I would like to say to the Iranian people I can understand why you are so angry about our intrusion into your waters”
Lieutenant Felix Carman

"It is unacceptable for these pictures to be shown”
Spokeswoman for Foreign and Commonwealth Office

"It is a charade set up for internal show in Iran and other parts of the Arab world”
Admiral Sir Alan West, former First Sea Lord

"Continued crude and cynical propaganda by the Iranians will get the regime nowhere. They must release the British detainees immediately”
Michael Moore, Lib Dem defence spokesman

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