By Kim Sengupta, The Independent
The British military were caught off guard when the service personnel was seized and they were taken by surprise again by the suddenness with which they were freed. But, behind the relief that the episode has ended peacefully, is the realisation that what happened has huge implications for the UK's presence in the Gulf.
An inquest is already under way into why no intelligence indicated that the sailors and marines were at risk, and into the weaknesses in the rules of engagement which allowed them to be captured with no resistance. Debate will also focus on whether the hostages should have allowed themselves to be paraded on television for propaganda purposes, and what they are told to do under such circumstances.
The wider question brought up by the hostage-taking concerns the challenges that British forces in Iraq, on land and water, can expect in an attritional confrontation with Iran. What happened in the Shatt al-Arab followed months of accusations by the US and UK that the Iranians have been supplying Shia militias in Iraq with sophisticated explosive devices which have claimed the lives of coalition troops.
The feeling is that more crises will follow. Admiral Sir Alan West, who has just left as head of the Royal Navy, told The Independent: " It is not just a military but very much a political matter as well. There will be a thorough debriefing of the service personnel who were taken prisoner, and a thorough analysis of lessons learnt. We had set up a system of communications with the Iranians on the Gulf but obviously, on this occasion, it did not work, and this is something we need to look at. The important matter is to decide how we interact with Iran."
Although British naval forces are in the Gulf under a United Nations mandate, they are not, despite some reports to the contrary, working under UN rules of engagement which have often been criticised for not being robust enough.
The coalition forces in Iraq have their own rules and the American ones differ from the British. Commander Erik Horner, of the US Navy, said: "Our rules of engagement allow a little more latitude. Our boarding team's training is a little bit more towards self-preservation." US personnel, said the commander, faced with the same situation as the British, would have opened fire.
For the British, a firefight was not a practical option. The two patrol ships that seized them had rocket-propelled grenades and heavy-calibre machine-guns. The British marines and sailors only had rifles.
Major-General Julian Thompson, who led the marines in the Falklands War, said: "We need to find out why there was nothing at hand to go to their rescue. We all have our views about the Iraq war - I have been publicly against it - but, if we are to put our forces in harm's way, then we must make a better job of looking after them."