More than 150 British personnel have died in Iraq since 2003
You might expect the mood in Basra to be one of rejoicing, given that an occupying army is pulling out. It is exactly the opposite, finds the BBC's John Simpson.
The British themselves tend to think of their time in Basra as a failure. The Americans told them bluntly that they were much too soft.
They patrolled in berets instead of helmets, and were not allowed to wear sunglasses; they did not want to seem menacing.
That worked well, until neighbouring Iran decided to stir up the militias to attack the British.
There was the famous scene in September 2005, shown on television sets around the world, when a crowd of Iraqis attacked a British armoured vehicle and set it, and its crew, on fire.
The British increasingly allowed the militia groups to behave as they wanted, in order to avoid the kind of battles which would cost British lives.
The government in London knew that public opinion at home, already turning strongly against Britain's involvement in the invasion of Iraq, would be deeply hostile to anything they regarded as a pointless loss of life.
The one big question here is, will Iran do what it did with the British, and stir up the militias against the American troops?
But as a result, women were attacked in the streets of Basra for not wearing Islamic dress, and shops which sold goods that were thought to be offensive were attacked. There was violence and theft.
Eventually the British withdrew from Basra city centre. American analysts said they would be chased out with their tails between their legs.
The Badr Brigade, one of the leading militias, claimed that it had scored a major victory in forcing the British out.
When I went to see the political head of the Badr Brigade, now that the British are leaving for good, I expected him to be crowing over his militia's supposed victory.
On the contrary, Forat al-Shar'a was full of praise for the way the British had behaved in Basra.
They were, he said, cleverer than the Americans, and had treated the Iraqis with great wisdom. They knew what had been required here, and the fact that the British were leaving peacefully is a genuine achievement.
That came from their worst enemy here.
Ordinary people I have spoken to agree. They are worried about the Americans, who they think will be aggressive and hostile, and they speak of the British leaving with genuine regret.
Yet the fact is that American tactics have changed during the past couple of years, and they have been a good deal less confrontational. They do not want to see their soldiers killed pointlessly either.
The one big question here is, will Iran do what it did with the British, and stir up the militias against the American troops? If so, the next two years could be difficult ones in Basra.
But if this does not happen, and the Americans run the city with a light hand, they too will be remembered with nostalgia instead of anger.