Kim Sengupta: Our 1,400 forces do not need to stay on under US control

Moving British troops out of Sangin to provide security for population centres in central Helmand makes sense. There is no intrinsic reason why, after the redrawing of the command structure in southern Afghanistan, more than 1,400 British troops should be kept in an American area of operation.

Sangin, however, is where the British military have lost the most lives in the Afghan conflict and there will be those who will claim that the handover to the Americans is betraying the memories of those who have fallen.

The handover of other British-controlled towns in Helmand to the Americans had led to the charge that areas where "blood and treasure" had been invested by the UK were being "given away". But the concept that land was somehow being "given away" is in itself rather strange. We are talking here not of some parts of Kent but sovereign Afghanistan whose security would, one day, be provided by the Afghan government. Whether this involves American control in the process is immaterial.

It is also difficult to see how British troops staying in Sangin, with the inevitable deaths, is, in some way, a homage to the dead. More boots on the ground where UK forces already operate will provide added security and help to lower the rate of casualties, and that, surely, should be the aim of the commanders.

There is, however, another aspect to the presence in Sangin which relates to a sensitive chapter in Anglo-American relations. There is little doubt that senior officers in the US military were critical of the way UK forces conducted themselves towards the end of their deployment in Iraq - letting militias impose a brutal regime in Basra and then withdrawing altogether when Washington was requesting that they stay on.

Holding Sangin, one of the most dangerous places in Afghanistan, some, at least, in the UK military hierarchy felt, was recompense for what happened in Basra. As one senior officer said: " When you are in alliance you have got to take the tough with the less tough. You cannot expect your ally to deal with all the tough situations."

But there is one vital difference between the two situations. Unlike Basra, the Americans have not been pressing for the British to stay on in Sangin, saying instead, that having US forces there would make issues of command and control simpler.

There is little doubt that the Nato mission in Afghanistan is approaching a critical period, with increasing scepticism about the war from the public and politicians. The time frame for an exit strategy is tight and the military strategy being revamped at a rapid rate. The move from Sangin is very much a part of that and it is pointless to read anything much more into it.