Maj Gen Andy Salmon insisted the armed forces were leaving Basra a safer and more optimistic place than they found it in 2003.
'I can put my hand on my heart and say we've finished this right,' he said.
Combat operations in Iraq will end on May 31 and nearly all of Britain's remaining 4,100 troops will leave by July 31.
The key turning point for Basra was a significant Iraqi army-led operation targeting militias last year.
Maj Gen Salmon admitted there was a lot to be done to make the city safe but predicted 'a very rosy future'.
He added: 'The threat that exists is very different from the threat a year ago.'