Ten years ago the displays of public grief surrounding the death of Diana, Princess of Wales, highlighted the complete separation between New Brits (who emoted to the full) and Old Brits (who thought it all rather tasteless and overdone). Today, the rejoicing over release of the 15 sailors and marines from captivity in Iran highlights the same split.

For New Brits, the photos of smiling, waving sailors with their shiny grey suits — and their lucrative newspaper serial rights —makes the heart grow warm. Leading Seaman Faye Turney is getting back to her daughter in time for Easter, after all, and possibly £150,000 richer. Meanwhile, Old Brits can feel nothing but sorrow at the humiliation that has been dealt to the Royal Navy and the United Kingdom. They want a large number of questions answered. Soon.

Few of us can guess at the terror involved in being handcuffed, blindfolded, put in solitary confinement and told that confession would mean “liberty” whereas refusal would entail seven years in an Iranian jail. “I really felt we were going to die,” said one marine, though his officer realised that instead of a mock execution the Iranians were only playing with their weapons. Yet it all comes down to training.

With proper preparation for such hardships — in what is, after all, the most dangerous theatre of operations on the globe — the captives ought never to have given the Iranians what they wanted in the way of propaganda. Eight British sailors were captured in similar circumstances by the Iranians in 2004; why have our troops not been trained properly in how to resist tough interrogation techniques?

New Brits might expect the 15 to be awarded a commendation, even a medal, for the hardships involved in being deprived of their liberty for nearly a fortnight. Old Brits will wonder why nobody is disciplined for the fiasco which led to them divesting themselves of the Queen’s uniform and then dressing in suits that look as if they were made by Ahmadinejad’s tailor.

In the war on terror we must expect captured civilians to appear on video providing propaganda for their captors. But for British servicemen and women to do so is a new and dangerous departure.

By ordering its personnel to be as obsequious as possible towards their captors so as to obtain quick liberation, the Royal Navy is letting down itself, the country but also crucially the captives themselves. It lets down the servicemen because their case is fatally undermined when they appear on TV in front of falsified maps that substantiate Iran’s argument.

It lets down the country by putting the service group’s supposed interests before the greater national interest. It lets down itself by allowing the world to see British sailors from one of our oldest and proudest units publicly thanking their kidnappers. There was a great deal of accumulated wisdom in the “name, rank, number” convention that seems to have been discarded by the modern navy.

The British boat crew were caught in a position when they did not even have the opportunity to defend themselves from capture. At the very least, our rules of engagement need changing. It is very likely that the Iranians had orders not to continue with the kidnap operation if it met resistance, as it was carried out under the very guns of the British warship HMS Cornwall. Yet because the Iranians knew that HMS Cornwall was under orders never to fire first, their daring plan succeeded.

The “no-first-fire” rule of UN forces was the reason that thousands of innocents died in Srebrenica and Rwanda. Opponents knew that if they didn’t attack UN forces they could do pretty much anything they liked. This is simply an updated version.

To state anything more than name, rank and serial number is all that a captured servicemen should ever do. These marines — New Brits to a man and woman — instead told Ahmadinejad, in the words of one of them: “Mr President, nice to meet you. We are very grateful for your forgiveness. We would like to thank yourself [sic] and the Iranian people.” Compare that with the behaviour of British POWs in any earlier war that one cares to consider and one appreciates the vast difference between New and Old Britain.

Of course POWs should not invite retribution, but was it necessary to go that far? An officer stood in front of a map of the Gulf telling the world what the gangster regime that kidnapped him told him to. Of course he can plead he was only obeying orders. Admiral Sir Alan West, the former chief of naval staff, has stated: “Our guidance to anyone in that position would be to say: Don’t tell them secrets, but if they tell you, ‘Say this’, well if that’s going to get you out, then do it.”

In fact, the Iranian decision to release the marines was taken with regard to any number of considerations, and the hostages’ behaviour in itself had no effect on it.

Hostage-takers everywhere will be hugely emboldened by the events of the past fortnight. The hardliners in the Iranian regime who were behind this coup will be strengthened by their success. As Ahmadinejad’s uranium-enrichment programme marches ahead, he has been lauded across the globe for his decency by Faye Turney, Captain Chris Air and Lieutenant Felix Carman. Meanwhile, the EU has praised Britain for her “restraint”, a sure sign that we have been humiliated. It was President Bush who got it right when he referred to the marines as “hostages”.

Recall the courage of the young American airman John McCain, who refused to be repatriated from the notorious Hoi An Prison in Hanoi unless his comrades were also repatriated, despite having had his limbs broken by his captors. Yet McCain, today a candidate for the US presidency, refused to aid the enemy in any way beyond stating his name, rank and serial number.

Orders or no orders, ponder the words of Royal Marine Lieutenant Felix Carman: “To the Iranian people, I understand why you were insulted by our apparent intrusion into your waters. I hope this experience will help to build the relationship between our countries.”

If you think that sounds fine, then you’re a New Brit. If your gorge rises, then you’re definitely not.

Andrew Roberts is the author of A History of the English Speaking Peoples since 1900

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