Defense Secretary John Hutton attended a memorial service at the base for 179 service members killed in Iraq, The Guardian reported.
"I think when the history is written of this campaign, they will say of the British military 'we did a superb job,'" Hutton said.
About 4,000 British troops remain in southern Iraq. Almost all are expected to be withdrawn by the end of May, with 400 to remain to train Iraqi security forces at the port of Basra, the major city in southern Iraq.
Iraqi Prime Minister Nouri al-Maliki, on a visit to London, signed an economic and technological agreement with British Prime Minister Gordon Brown. Maliki also met with representatives of major British companies at an investment conference.
Britain was the major U.S. ally in the invasion, although the war was never popular with the British public. Conservative Party leader David Cameron called for an inquiry into the decision to invade, similar to one held on the Falklands War, which was conducted in private hearings.