According to an ABC News exclusive at the Blotter, it would be "a miracle" if they were not:

"It is not a matter of if there will be an attack, but how bad the attack will be," an intelligence official told ABCNews.com.

Authorities say they are seeking at least 18 suspected suicide bombers.

This is an unprecedented warning that would not have been released unless the Brit authorities had hard intel. With the death of an innocent man after the 7/7 bombings, one would expect that the British security forces may not be so quick to respond should they suspect an event of taking place. Here's hoping that they can deter any attack and arrest those responsible.

France is also worried about being attacked as Ayman al-Zawahiri supposedly called them out in his latest video tape dispatch. When will nations such as France realize that they can appease and apease, but eventually you have to face the enemy and that enemy seems to be coming right at you.

No word on any reports of threats (outside the one from Zawahiri) in the U.S.

In related news, this can't exactly be comforting to the UK authorities:

A British soldier has been charged with passing secret information linked to the military campaign in Afghanistan to Iran, The Times has learnt. Corporal Daniel James, 44, appeared at City of Westminster Magistrates' Court in London yesterday, charged under Section 1 of the Official Secrets Act with communicating information "useful to the enemy".

Much more here.