I'm not too old to take over from Gordon says Clarke

In a forthcoming radio programme about the rise of a new "Jam generation" in politics who grew up when Paul Weller's band was in the charts, Mr Clarke, 58, dismissed the idea that power was shifting to younger leaders such as David Cameron and Nick Clegg.

He said: "Half the electorate at the next election is going to be over the age of 58, which is a hell of a figure when you think about it. If you simply say that only people who are a lot younger than that can be qualified to lead the country, you're accentuating a very serious division between the people of the country and the Government of the day of whatever party."

He added it was a "mistake" for the Conservatives and Liberal Democrats to think that a leader in their early forties would impress voters and counselled against Labour following suit.

Mr Clarke said: "I don't think it's evident that either David Cameron or Nick Clegg [both 41] will be able to appeal to large sections of the electorate because their experience even on grounds of age alone is not wider. You see John McCain [71] coming through in the US ... and I think it's not obvious that this ever-accelerating trend towards having a younger person will be what people will look for in their political leaders."

His comments are a sign that he intends to challenge David Milliband, the 42-year-old Foreign Secretary tipped to succeed Mr Brown, who is 57 next week. He said he would still consider a run "when David Cameron loses and when Gordon Brown goes, whenever it may be".

Asked if he would consider himself too old to run for the Labour leadership when he was 60 or over, Mr Clarke said: "No, of course not. You have to look at the moment. It's not an issue about age at all - it's about capacity, quality, politics and so on. The country's had many great leaders who are really quite elderly and I think that's equally possible in the modern era."

Mr Clarke also criticised the move at Westminster to professional politicians with no experience of life outside politics. "It does raise an issue of the relationship of the political class as a whole with voters because people say, 'Well what does that individual know about the kind of lives we're leading?'" On the programme, shadow Chancellor George Osborne claims Mr Brown is on the wrong side of a shift in the political generations, accusing him of being "stuck in a 20th-century timewarp".

Mr Cameron added: "The new generation understands a lot more the importance of social and cultural change. Generational change brings an advantage to that extent. You can take a fresh look."

The Jam Generation, presented by Anne McElvoy, is on BBC Radio 4 this Sunday and next at 10.45pm.