Britain ended its troop presence in Iraq, concluding six years of military involvement in the country that began with the US-led invasion that ousted Saddam Hussein.
Under a deal between Baghdad and London signed last year, the last of Britain's forces left this week ahead of a 31 July deadline for their withdrawal, a spokesman for the British Embassy said.
A small contingent of around 100 naval trainers currently de-camped in Kuwait could return once Iraq's parliament has considered a new agreement between London and Baghdad. Parliament will reconvene in September.
The agreement has been endorsed by Iraq's cabinet.
Britain will continue to offer training to Iraqi army officers as part of a NATO mission in the country and will provide training for Iraqi military personnel on courses in the UK.
Today's withdrawal deadline comes just a day after the UK launched an inquiry into its role in the war. The probe will question key decision-makers, including ex-prime minister Tony Blair and be free to criticise government decisions.
Under Mr Blair, Britain was a key ally of the US when president George W Bush ordered the invasion of Iraq in March 2003 to topple Saddam.
Baghdad and London signed a deal last year that said all British soldiers in Iraq would complete their mission, which in recent months focused on training the Iraqi army, by June, before withdrawing completely by the end of July.
Since the invasion, 179 British soldiers have died in Iraq.
It also comes a month after US forces pulled out of Iraq's towns and cities as part of a deal between Baghdad and Washington that calls for all American soldiers to leave Iraq by the end of 2011.
Meanwhile, six bombs struck Shi'ite mosques across Baghdad police said, killing at least 28 people and angering Iraqis who blamed local forces now taking over from U.S. soldiers for failing to protect them.
The blasts, which wounded at least 130 people and appeared to target Shi'ite Muslims taking part in prayers, were a reminder of militants' persistent capabilities in Iraq despite the sharp drop in violence over the last 18 months.
In the worst attack, a car bomb struck people praying in the street outside a crowded mosque in northern Baghdad's Shaab district, killing at least 23 people and wounding 107.
One Iraqi at the scene said a car parked near the al-Shurufi mosque in Shaab exploded midway through the service.
Shi'ite religious gatherings in the past have been targets of Sunni Islamist al Qaeda, which regards Shi'ites as heretics..
The attacks raise questions about Iraq's future just a few weeks after U.S. combat soldiers withdrew from urban bases and as Washington prepares to pull out all U.S. troops by 2012.
