Having already drawn down the divisional headquarters a month ago, the UK forces have handed over command to US forces and begun withdrawal - marking the transition from a combat mission to one of rebuilding.
UK Defence Secretary John Hutton joined forces stationed at the Contingency Operating Base (COB) outside Basra for a day of reflection, commemoration and celebration of British achievements in Iraq since Operation Telic was launched in 2003.
"Today marks the end of the UK's combat mission in support of the government of Iraq, but it does not mark the end of the UK's relationship with Iraq," he said.
The UK has outlined the country's future with Iraq as one of partnership and is currently discussing the precise scope of our future military activity with the Iraqi Government.
At present around 400 UK military personnel are likely to remain in Iraq beyond July. They will continue to provide specialist training and mentoring support to Iraqi forces within the Iraqi Navy and also play a key role in military officer training.
Commander of the 20th Armoured Brigade, Brigadier Tom Beckett said: "We know we leave the security of Basra province in safe and capable hands. Trained by the UK, the 14th Iraqi Division is a professional counter-insurgency division. It has strong leaders, strength in depth in its junior ranks, and brave and dedicated soldiers."
Other long-term tasks include Royal Navy ships continuing to patrol the Gulf area contributing to the defence of Iraqi territorial waters and its vital oil platforms.
The Government of Iraq has also indicated it would like to continue arrangements whereby its military personnel receive military training and education in the UK.
UK Chief of Defence Staff, Air Chief Marshal Sir Jock Stirrup said that, above all, the mission was about the Iraqi people.
"This whole endeavour has always been about the Iraqi people, about the Iraqi armed forces and the rest of the Iraqi security forces who have fought with such bravery and who have accomplished such great things on behalf of their great nation," he said.
"It is about the ordinary men, women and children of Iraq. It is about them being able, with confidence, to construct their own future. It is about them being able to have a say in the governance of their own country."
By Daniel Garrun.