For those of you from foreign parts, April 1 is known in the UK as April Fool's Day, because it is the one day of the year when we are allowed to play practical jokes on one another. This morning the Daily Mail tried to convince us all that Tony Blair had painted the door of No 10 red. Of course none of us fell for this joke. Then the truth dawned. It's Tony's April Fool gag on the Daily Mail!