Britain will end its military mission in Iraq in spring, six years after coalition forces invaded the country, Gordon Brown will tell the House of Commons today.

After weeks of fraught negotiations over the role of the remaining British forces, Mr Brown finally sealed the exit deal at a meeting with Nouri al-Maliki, the Iraqi Prime Minister, during a ten-hour visit to Baghdad and Basra yesterday.

The protracted military campaign involving 100,000 British troops has cost the Exchequer £7 billion and 178 military personnel have been killed.

Mr Brown said that British forces would be leaving Iraq “a better place”. Yet hours after he met Mr al-Maliki, two bombs in Baghdad killed 18 and wounded 53.

Under the new agreement, the remaining 4,100 British troops will cease all military operations before an Iraqi-imposed deadline of May 31. All but a few hundred will leave by July 31.

Speaking at a press conference alongside Mr al-Maliki, Mr Brown sought to justify Britain’s work in Iraq. “It is important to remember we have been engaged in the most difficult and challenging of work: the task of overthrowing a dictatorship, the work of building a democracy for the future and defending it against terrorism. And of course the work of giving people an economic stake in the future of Iraq. We leave Iraq a better place as a result of it.”

Britain and Iraq have been engaged in tense negotiations over the rules of engagement for British forces after the UN mandate expires in January.

Iraq wanted to limit Britain’s role to training operations and Downing Street sent Simon McDonald, the Prime Minister’s chief foreign affairs adviser, to conduct negotiations.

Downing Street insisted last night that a “commonsense solution” had been found and that, in practice, nothing would change for the troops.

After July 31 there will be only 400 British military personnel in the country to carry out officer and naval training, at the request of the Iraqis. These are expected to leave by the end of next year. Several thousand American soldiers will move into the British base at Basra airport, primarily to guard the supply routes from Kuwait. Mr Brown said that Britain should feel no embarrassment as the US forces “will be doing a different job”.

He said that British forces were able to withdraw because they had achieved all four mission objectives, which included training Iraqi security forces, political progress in economic rebuilding and a return to normal civil aviation at Basra. More than 20,000 troops had been trained, local elections were scheduled for January, the IMF predicted growth of 10 per cent this year and the handover of Basra airport was expected next month.

However, this four-point exit plan was devised by Mr Brown only in July.

British officials highlight the reduction in the number of bomb attacks in Basra as evidence of progress on security, from 38 in May last year to one last month. “In Basra, polling shows that more people are concerned about the economy and jobs than bombs,” Mr Brown’s spokesman said.

The exit agreement, which applies to Australia, Romania, Estonia and El Salvador, plus a Nato force of 200 as well as Britain, was presented to the Iraqi Parliament on Tuesday. It includes a provision for the Iraqi Government to request an extension of the British military presence. However, neither side expects it to be used.

Times Recommends

• No apology for Germany’s own Nazi victims
• Intricate web of fear and hope tying down deal
• Victims remembered a year after Mumbai attacks