Tony Blair's media offensive is persuading voters of the case for war, a new opinion poll has suggested.

According to MORI, just one in four voters would oppose an attack on Iraq come what may.

The data comes at a crucial time for the prime minister and will boost Downing Street's hopes that public hostility can be overcome before military action begins.

The study found that the public mood towards war was softening - although support for war is far from unconditional.

Securing UN backing for a second resolution appears vital, the survey suggests.

Unless proof emerges that Saddam Hussein is concealing weapons of mass destruction, only one in four people would support war.

Following Tony Blair's concerted media blitz, MORI finds a 10 per cent swing in favour of war since mid-January.

Public support for the prime minister's stance had been plummeting since September, from a high of 71 per cent in favour of a UN-led conflict.

The latest figures suggest the prime minister is finally getting his message across.

Those opposed to war without UN approval still remain in the majority, yet the report shows opposition has declined by 10 per cent, down to 67 per cent since mid-January.

However, support for the British position still remains volatile, as people wait to hear the report from UN weapons inspectors.

Three in five people would accept war without UN approval if the inspectors find evidence of Iraqi duplicity, the survey finds.