It wasn't the elbow, it wasn't the worsening average, it wasn't even his team-mates disappearing "up their own backsides".
Graeme Swann's grandmother, Mina Swann, has claimed the real reason the spinner retired in the middle of an Ashes series was because something "nasty" must have happened with a certain, unnamed, Australian player.
Mina, 89, from Blyth, Northumberland, told North East's The Journal that she was upset her grandson called it a day, and found out when she turned on the television late on Sunday night.
"There is something gone wrong there and I blame the Australian players. Not all the Australian players, a certain one," she said.
"When the team went down to Australia and that young lad [Jonathan Trott] came back, there was something going wrong then.
"I do not think they have been [made] very welcome, the team. He is not easily upset, there is something nasty happened."
Mina added: "He was as happy as Larry. He adored his cricket. It is a damn shame, he has lived for that game, he has done everything for that game.
"I am very disappointed because that is one thing I look forward to. I will be very disappointed when he is not there."
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