Maynard was set to retire at the end of this season

The 39-year-old will work with England's Test and one-day squads, as well as players selected for England's National Academy and age-group teams.

"I have spent 20 years with Glamorgan and leaving Sophia Gardens behind will be a big wrench," Maynard said.

"But this is a terrific opportunity for me and I am very excited."

Maynard took on a part-time role as England's assistant coach for the one-day series in Zimbabwe and South Africa last winter.

"I really enjoyed being a part of the England management team during the winter, and am very pleased that I am now going to be involved with England's elite cricketers on a longer-term basis," Maynard added.

Maynard will now begin his new coaching duties on 9 June, ready for matches with Bangladesh and Australia, on an initial contract going through until the end of the 2006 domestic season.

He had originally intended to return to complete his 21st and final season at Glamorgan, but his record-breaking career has now come to a premature end.

Matthew has made a terrific contribution to cricket in Wales Glamorgan chief executive Mike Fatkin

A bout of bronchial pneumonia has restricted Maynard to just one County Championship appearance this season.

Glamorgan chief executive Mike Fatkin said: "It's disappointing to be losing a player of Matthew's calibre but he had indicated his intention to retire at the end of the season anyway.

"As opportunities such as these don't come up too often we're happy to help in any way we can.

"Matthew has made a terrific contribution to cricket in Wales, both on and off the field, for more than 20 years and his will be substantial shoes to fill.

"But we're delighted that he's been identified for such an important role and we've no doubt that he will be a great success in his new position."

Maynard has scored nearly 25,000 first-class runs, and last season broke Glamorgan's record for first-class centuries.

He won four England Test caps and played in 14 one-day internationals.

The Welsh county have moved quickly to fill the gap left by Maynard as they try and halt their alarmingly poor start to the season, signing India skipper Sourav Ganguly as an overseas player.