Mr Clegg, the Liberal Democrat’s home affairs spokesman, said he agreed with Tory leader David Cameron that politicians are entitled to a “past private life”.
A string of Cabinet ministers owned up to smoking cannabis in July after Home Secretary Jacqui Smith said she had used the drug at Oxford University in the 1980s.
Mr Clegg was also asked whether he had used illegal drugs in a series of questions emailed to him. He replied: “One of the things I agree with David Cameron on is that politicians are entitled to a past private life.”
The Home Office is currently reviewing the decision to downgrade cannabis to a class C substance - and Mr Clegg believes the classification of drugs should be completely overhauled.
He said: “The present debate on classification of drugs is nonsense, with politicians second guessing science and evidence. We need a total overhaul of the system so that classifications are based on facts rather than the prevailing mood of tabloid newspapers or Home Secretaries.”