Harmer will take up a post with the Australian Academy

Harmer, who has improved the side's one-day world ranking from fifth to third during his two-year tenure, will take up a post as biomechanics specialist with the Australian Cricket Academy.

His current deal with the England and Wales Cricket Board (ECB) ends on 1 July, five weeks before Clare Connor's side take on South Africa in the first of two Tests.

But he has offered to stay with the side through the summer if required, whether or not a full-time replacement is found.

England also take on South Africa in a three-match one-day series from 13-17 August.

The loss of Harmer, who led the Australia women's team to three World Cup finals from 1992-2000, will also be felt through the domestic game.

"He has taken giant steps forward in ensuring our aim that England are one of the top two women's teams by 2007," said Gill McConway, ECB executive director of women's cricket.

HARMER'S ENGLAND RECORD 2000/01 World Cup: Fifth behind NZ, Aus, India and SA 2001 Ashes: Lost Test series 2-0 and ODIs 3-0 2001/02 India tour: Lost ODI series, drew one-off Test 2002 ODI series: Beat India in all three games, but lost to NZ in final 2002/3 ODI series: Finished third behind Aus and NZ, beating India twice 2002/3 Ashes Tests: Lost series 1-0, with loss in Brisbane and draw in Sydney

"Together we have implemented a new structure of coaching for the women's game with regional based centres and Super Fours, the domestic competition for elite women's players."

In an ECB statement, Harmer said he had been pleased by the development of the team under his tutelage.

"I wish them all the very best in the future and look forward to seeing them again when they visit Australia," he added.

Connor expressed her disappointment at Harmer's decision.

"We have relished the opportunity to work with one of the world's best coaches, and we have all learnt so much from John," she went on.

"We must build on the solid foundations he has established and we are all much better players than we were two years ago".