I hope the club can continue to build upon the considerable progress the team has achieved over the last two seasons George Burley

Burley saved the club from relegation after joining as interim manager in March 2003 and led them to the play-offs in the 2004-2005 season.

Derby director of football Murdo Mackay has also offered his resignation.

"My position has become untenable," said Burley, but Derby chairman John Sleightholme accused him of not making clear "his real reasons" for resigning.

Sleightholme said: "George raised a specific concern with the board, the board had a meeting and complied with George's request and he agreed to continue as manager.

"The board, having satisfied George's requests, are disappointed he has not made clear his real reasons for leaving."

Mackay's resignation has yet to be accepted by the Derby board.

Burley was thought to have had a difficult relationship with Mackay.

"I offered my resignation late on Monday," Mackay told BBC Sport. "I was surprised to hear about George's own resignation."

Burley is believed to have been upset midfielder Tom Huddlestone was sold to Tottenham against his wishes.

The former Ipswich boss also said newspaper allegations about his conduct had "deeply hurt him", although the club last month publicly denied they had launched an internal inquiry.

This has been on the cards since Huddlestone was sold on the cheap against Burley's wishes From R Have your say on 606

The Scot's departure will be a blow to the club who he saved from relegation in his first season before leading them to the semi-finals of the play-offs during the last campaign.

"It is with great regret I wish to announce my decision not to continue as manager of Derby County Football Club," announced Burley.

After saving Derby from relegation, Burley had been rewarded with a two-year deal in May 2003.

"It has been an honour and a privilege to work for this great club and to have enjoyed a memorable relationship with such special fans."

He added: "I hope that the club can continue to build upon the considerable progress which the team has achieved over the last two seasons, and I wish the club every success in the future."