The government has left Britain with a moral obligation to improve the situation in war-torn Iraq, Sir Menzies Campbell has said.

Speaking at the party's conference in Bournemouth on Monday, the Liberal Democrat foreign affairs spokesman also attacked the prime minister's failure to live up to his promises on the Middle East.

As the death toll in the country continues to mount, he told delegates that Iraqi security forces were "inadequate and undertrained".

And the resulting crisis had undermined the UK's international reputation, Sir Menzies added.

"Our reputation and respect have been diluted and dissipated, and all because of Iraq," he said.

"Never mind our record on Kosovo or Sierra Leone or overseas aid. Around the world Britain is associated with unilateralism in Iraq and double standards in the Middle East."

Fragile

There had been no weapons of mass destruction and no progress on the Middle East roadmap, Sir Menzies said.

Instead, the war had produced a country "so fragile that the secretary general of the United Nations doubts if the essential elections can be held".

"And for all this our country has a moral responsibility, a moral responsibility imposed on all of us by our government, a moral responsibility so acute we have no option but to stay," he said.

Renewing Lib Dem calls for a phased withdrawal of UK troops, Sir Menzies said a new British foreign policy should seek to become "a model European country".

But he added that there would need to be reform "so that Brussels only acts where a collective approach will serve our interests best".