Sir Menzies Campbell has defended his record as the Liberal Democrat leader but acknowledged that his performance against Tony Blair remains "a work in progress".
Speaking at a lunch for political journalists, Sir Menzies was asked about his weekly performance at Prime Minister's Questions and acknowledged that it remained a "challenge".
He said: "PMQs is a rather different experience from other parliamentary occasions we have to face. I remember Paddy Ashdown found PMQs a rather different experience and David Steel and Roy Jenkins. It is a work in progress. It is a challenge and I am determined to meet the challenge.
"If PMQs was the only political test in this country William Hague would still be leader of the Conservative Party."
Sir Menzies criticised a party campaigns organiser after he appeared to urge activists to leaflet the seat of the late Conservative MP Eric Forth the day before his funeral.
The party's London region campaigns chairman, Pete Dollimore, sent an e-mail advising members to travel to Mr Forth's Bromley and Chislehurst seat to distribute leaflets.
By convention parties do not campaign for a by-election before the funeral of the former MP has taken place.
In Mr Dollimore's e-mail, he gave details of direct trains from central London and said the local party wanted to "clear the decks" and would "appreciate" help getting out leaflets.
Sir Menzies said that he did not know about the e-mail. "Eric Forth was a friend of mine. Eric Forth was born within a mile of me. He went to school about half a mile away. I deprecate any effort to begin electioneering under any circumstances in any by-election until the writ has been moved by the party with responsibility for doing so. If that were done I disapprove and I will make sure my disapproval is known."