A spokesman for Nick Clegg said an Algeria-related tweet sent from Lib Dem MEP Graham Watson's account was "sick and offensive."
We have not been able to verify whether this tweet is authentic.
But whoever it is from, it is clearly sick and offensive and utterly condemned by Nick Clegg.
The tweet, since deleted, read: "Al Qaeda 1, @David_Cameron 0".
I'm told Mr Clegg was "furious" when he heard about the message. The party is still stressing, however, that they can't be sure Mr Watson himself sent it.
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The Sherlock actor made the comment while he received an award for his humanitarian work.