Michael Vaughan has accused Jonathan Trott of celebrating with South Africa's players after England lost in 2008.
Vaughan claimed he saw South Africa-born Trott, who has been included in the England party to tour South Africa this winter, congratulating the opposition after the match at Edgbaston.
The Proteas sealed a series victory by winning the game, and it was Vaughan's final Test.
Writing in his new autobiography, Time to Declare, Vaughan said: "It was a sad day for English cricket that on my last day against South Africa I saw Jonathan Trott celebrating with South Africa, when the week before he had been our 12th man at Headingley.
"I was going into the press conference and I saw him patting them on the back. It hit home what English cricket has become like."
Trott enjoyed a dream Test debut in August of this year when he memorably hit a century on debut as England clinched the Ashes at The Oval.
Vaughan added: "The selection of Jonathan Trott after much fevered speculation proved an excellent decision. He immediately had that look about him of being comfortable at the highest level, and could prove to be a more stubborn version of Kevin Pietersen.
"I suppose you might wish Trott was a bit more English, but after such a brilliant debut it appeared we had found another high-quality batsman."
The Warwickshire right-hander, though, has insisted that his commitment to the England cause is absolute.
Trott said in the Daily Mail: "My commitment to England is 100 per cent. I've spent seven years working hard to be able to wear the Three Lions and in that time my allegiance has never wavered."
Trott is one of a handful of South Africa-born players in the England Test set-up, after captain Andrew Strauss and Pietersen.