The chief executive of Oxford City Council may quit his post tonight at a potential cost to the taxpayer of more than 157,000, writes Mark Templeton.

Bob Block, 49, who earns 70,000 a year, has said he wants to take early retirement.

He is asking political leaders for their views.

But if he goes, his pension fund would have to be topped up to the tune of 157,000, in addition to the cost of any golden handshake he might receive.

Mr Block dropped his bombshell announcement to party leaders on Tuesday night. Not even his closest staff were aware he wanted to leave. He has been in the post since 1988 and is well-respected among colleagues and politicians alike.

It is understood he wants to leave for personal reasons, but he is also thought to have asked leaders if someone younger should take over to head the massive modernisation of local government programme over the next two years.

Labour group leader Alex Hollingsworth said they were concerned at the financial implications to the taxpayer if Mr Block retired. He said: "His pension fund would have to be topped up by 157,000, plus there would be other payments the council may wish to make for his good and long service.

"Add this to the costs of recruiting a new chief executive, which could be anywhere between 20,000 and 30,000, and you will see the huge finances involved.

"But we'll have to weigh this up against having a chief executive in post who really wants to take early retirement."

Mr Block, who is married with three children, told council leaders he was prepared to stay if they felt that was right. Liberal Democrat leader Corinna Redman said she believed it was time for a change.

She said: "Bob has done an excellent job over the last 12 years.

"But we are about to undergo a radical change and it might be time that someone else who is really enthusiastic about modernising local government should be given the opportunity to see the council through these changes."