Gordon Brown opted for a classic British compromise when he decided to reduce significantly the number of British troops in Iraq, but to maintain indefinitely a token presence in the US-led coalition.

Ever since he took over as Prime Minister from Tony Blair, Mr Brown has been under pressure from the public and his own party to end Britain’s role in a deeply unpopular conflict.

While some Labour supporters wanted the Government to withdraw British forces from Iraq completely, as Spain, Italy and other countries have done, that move was never a realistic option for Britain.

British forces may seem small in comparison to US troop numbers to the north, but they occupy a strategic part of Iraq, including the country’s largest oil fields, its only access to the sea, the main supply routes from Kuwait and the tense border with Iran.

The Government did not want to be seen to abandon southern Iraq and force the already overstretched US military to take its place. Nor did it want thousands of British troops tied up in Basra exposed to a deadly urban insurgency.

The result was the compromise announced today.

Britain will remain in Iraq, but by the spring the force will shrink to 2,500. This will be enough to control Basra airport, the British headquarters, support Iraqi forces and US convoys in the area and field an armoured battlegroup several hundred strong in an emergency.

It also means that Britain will cease to be a serious player in Iraqi security terms.

It signals a clear break with President Bush’s “surge” policy of reinforcing the US military with tens of thousands of additional troops.

Mr Brown may have had one last motivation for the timing of his troops withdrawal. While speculation about an early election in Britain has now died down, it is perhaps no coincidence that the sharp reduction in British forces will coincide neatly with the next most likely date for an election - spring 2008.

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