Sir Menzies Campbell is too old and should stand down to make way for a younger leader, Lord Owen, the former leader of the Social Democrat Party, said today.

In an interview with the Parliamentary Monitor magazine, the former Labour Foreign Secretary describes the Liberal Democrat leader as "only a couple of years younger" than himself and argued Sir Menzies should be replaced by a "young Turk". Lord Owen is 68. Sir Menzies is 65.

The cross-bench peer suggested change should "happen before the next general election", and noted: "It is a pity they have a leader of the older generation."

Tony Blair is 53, Gordon Brown is 55, and David Cameron is 40.

Lord Owen highlighted the credentials of Chris Huhne, 52, the party's environment spokesman. Last year, he failed in his bid to challenge Sir Menzies for the party leadership following the resignation of Charles Kennedy, 47, who reliquished the top job after admitting to a drink problem.

"Chris Huhne has produced some very good ideas on the environment and it was a thoroughly good thing for him to challenge for the leadership," said the peer.

Lord Owen's intervention will not be welcomed by the leadership. While there are rumblings on the back benches about the party's lacklustre performance in opinion polls, there does not appear to be much appetite for a second leadership battle in a year.