Bowling coach Troy Cooley says he has decided to return to Australia because the England and Wales Cricket Board hesitated over offering him a contract.
Cooley asked for a two-year deal in May but claims the ECB were only prepared to offer him a one-year contract.
He has now agreed to return to his homeland and occupy a similar role with the Australian Cricket Board.
Cooley said: "I would have been happy to stay with England - but May was really the time to have settled it."
Masterclass: Troy Cooley on reverse swing
The Australian's new contract with the ACB is believed to offer only slightly better terms than he is currently on with England.
"By the time I got around to negotiating with them (the ECB) again, towards the end of the Ashes, other people were talking to me," Cooley told The Guardian newspaper.
"They picked up on the fact that I would soon be out of contract. A door got opened up.
"I am an Australian, and at some stage, I suppose I was always going to return"
"The money was not a huge factor, though I do believe in a fair day's pay for a fair day's work.
"I am an Australian, though, and at some stage, I suppose, I was always going to return. It's happened sooner than I expected, but it's a great opportunity."
Cooley joined England in 2003 and has been hailed as the man who developed the talents of Matthew Hoggard, Steve Harmison, Andrew Flintoff and Simon Jones.
England's focus on reverse swing was a key element of England's Ashes triumph.
He said: "It's been a fantastic journey and I've enjoyed every minute of it, not only helping the bowlers to perform as a unit but also playing a part in the setting up of what is now a very impressive fast-bowling programme."
Cooley does not know for certain whether he will travel with the England team for the tour of India early next year, insisting it is "very much (coach) Duncan Fletcher's call".
He is set to take up a similar job in his native Australia in May 2006.