Mr Winter described his deputy as a 'valuable' colleague

Aidan Rave said he lacks confidence in elected mayor Martin Winter and John Mounsey, cabinet member for transport, said the council is not open enough.

Mr Winter is under investigation over his election expenses and is involved in a second, separate police inquiry.

Doncaster Council is one of only 11 local authorities to be led by an elected mayor.

I might be proved wrong but I've done it for what I believe is the right reason Former deputy mayor Aidan Rave

Mr Rave told the BBC he disagreed with the direction in which the Labour-run metropolitan borough council was being taken.

He said: "I think there's a lack of confidence there otherwise I would not have taken the decision I have taken today but really that is more for Martin Winter to worry about rather than me.

"I have taken the decision I have taken today after a long period of reflection.

"I might be proved wrong but I've done it for what I believe is the right reason."

Government watchdog

In a statement Mr Winter said: "Aidan has been a valuable member of the council's executive for the past five years and also my deputy during this time.

"I am sure he will continue to work hard for his constituents and the Labour Party, continuing to play a role in delivering Doncaster's new found success."

Last month it emerged that South Yorkshire Police were investigating alleged irregularities in Mr Winter's election expenses following claims he should have included a meeting at Doncaster Rovers ground.

In a separate inquiry, police are investigating the way a community project, once run by Mr Winter, was set up after being criticised by a government watchdog.