Liberal Democrat leadership contender Chris Huhne has laughed off comments he allegedly made promoting the use of marijuana while a student in the 1970s.
Mr Huhne said he had been a 'revolting teenager'
He was asked if he stood by words in an article attributed to him that "hash" was useful when "work, or love, or lifestyle become too intolerable".
During a BBC News 24 debate, Mr Huhne said he had been "a revolting teenager" and he did not "stand by" such views.
Rivals Sir Menzies Campbell and Simon Hughes also took part in the show.
Mr Huhne, a Lib Dem Treasury spokesman, was alleged to have written his comments in a student magazine, but said: "I must say I don't recognise that quote."
Acting leader Sir Menzies and party president Mr Hughes both said they would leave the issue of cannabis's legal classification to "expert" medical advisers.
The three candidates disagreed on the issue of withdrawing forces from Iraq.
Mr Huhne said he wanted to set a "deadline", while Mr Hughes suggested this should be 31 December this year.
But Sir Menzies, who is also the party's foreign affairs spokesman, dismissed ideas of a fixed target date and said a "coherent strategy for exit" was needed, including training Iraqi security forces and establishing political stability.
The candidates also discussed the environment and whether Scottish and Welsh MPs should vote on England-only issues.
The News 24 debate, chaired by the channel's chief political correspondent, James Landale, came a week after the party's surprise by-election victory in Dunfermline and West Fife.
The Lib Dems' former Scottish chief executive Willie Rennie overturned a 11,500 Labour majority to take the seat, where Chancellor Gordon Brown lives.
The party's 73,000 members have two weeks left to decide who will replace Charles Kennedy as leader.
All three camps say the race is still wide open.
The candidates do not have access to party membership lists so are unable to canvass voters directly - or get a feel for the likely result.