WILLIAM GALLAS was on holiday in the summer of 2006 when he saw his number at Chelsea come up. His No 13 shirt bore the name of Michael Ballack, the club’s new signing. “I was in Guadeloupe [when] Didier Drogba phoned. ‘William, they’ve given away your number! What’s the story?’ I didn’t understand it. Why had Mourinho acted like that?”

The incident confirmed that relations between Gallas and Chelsea, strained for months by the terms of a contract extension, had reached a new low. Gallas was in the Caribbean against the instructions of Jose Mourinho, then the club’s coach. Gallas recalls in his autobiography, inset, just published in France and whose title roughly translates as Case for the Defence, that Mourinho had sent him a text message as his team qualified for the World Cup final in early July. “He congratulated me. But he added that ‘unfortunately’, I had to be back on July 29, barely 20 days after the final. It was unbelievable. The competition over, I left as arranged for my holidays on July 12. I called Mourinho to ask him for some extra days. I just needed another five.

“He answered, ‘I know what you are asking, but it’s not possible. You have to be back on the 29th’. In the end I took my five extra days. So he was furious.”

The saga of Gallas’s pay demands had been going for 10 months. “I asked for a sum that was completely reasonable given that I was the player with most appearances [at that time] behind John Terry, and that Barcelona had offered a position at centre-half. At Chelsea not every position in the defence was covered in the squad because they had a very versatile player: Me. There’s only one other who can juggle the positions like I did: the great Paolo Maldini. Chelsea say I asked for the same salary as John Terry, which is not true. I must have been about the 10th-best paid player and I asked to be the third or fourth.”

When he did return from holiday, Gallas explained he wanted to leave Chelsea. “It was a question of respect. The irony is that the following year John Terry went through a similar episode with his salary. He told me how much he too felt disappointed.”

Gallas joined Arsenal on transfer deadline day that August. A few days later, Chelsea released a story that Gallas, had he stayed, had threatened to score an own goal. Gallas denies this, and says his parting words to Mourinho were: “I don’t have the heart to play for Chelsea. You can put me on the pitch, okay, but if my heart’s not in it and I am not focused, there’s a risk I’ll make the kind of mistake I don’t normally make. We might let in a goal or stupidly lose a game.”

William Gallas: La parole est à la défense (Editions du Moment, €16.50)