The two politicians often make every effort to look friendly in public, but their true feelings about one another are always betrayed by their gestures, according to Peter Collett, a psychologist formerly based at the University of Oxford.

Even their best attempts to pull together for the cameras fail, as they try too hard and create an unconvincing parody of true friendship, he said. During Mr Blair’s party conference speech in 2003, Mr Brown adjusted his clothes 25 times, bit his lip 12 times, touched his face 35 times, fiddled with his cuffs 29 times, uncrossed his arms 36 times and looked away 155 times, all indications of his frustration with his boss, Dr Collett told the British Association Festival of Science in Norwich.

“Gordon looks desperate to show support, but his smile is just a grimace,” he said. “He looks incredibly uncomfortable when Blair is in the limelight. There is a lot of nodding, but when he is nodding he is looking sick.”

Mr Blair’s attitude is no less contemptuous. “In a photo of the two published this week, Tony’s nose looks like someone’s farted. He pulls a face that’s explicitly consistent with what happens when the light’s too bright, or the facial gesture that’s common with a bad smell.”

The pair’s most ostentatious attempt to look united, in last year’s party political broadcast directed by Anthony Minghella, was a disaster because they overcompensated for their mutual dislike, Dr Collett said.

“The Anthony Minghella party political broadcast last year was full of body language fibs. When you are talking to me, I’ll give you my full attention only if I think you are of very high status or if I love you. On that party political broadcast, they are staring at each other like lovers. It is completely false.

“The relationship between Tony Blair and Gordon Brown is an endless game of political poker.”

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