Overcoming public cynicism about politics will be vital to Liberal Democrat fortunes, Charles Kennedy has warned.

The party leader told delegates at the Brighton conference on Monday that one of the biggest challenges would be appealing to the growing number of non-voters as well as the traditional floating voters and supporters of rival parties.

During an unscripted question and answer session, Kennedy said the public was increasingly being turned off by the cynicism in Westminster.

"People do want to engage with their politicians if they think they're listening," he said.

Repeating the research conducted by the party, Kennedy argued environmental politics would also bring in disaffected voters.

He admitted the party was not making enough of its policies on what is "an increasingly defining agenda".

Kennedy praised the fact that the party conference continues but, with facilities such as video links now available, he hinted that a fresh approach could be taken.

"Technology has changed and maybe we need to think more about that. There's people out there who are interested in the Liberal Democrats. They might not join but would like to have an input," he said.

He also said the party would have to build on its youth and students wing and accused the Conservatives of being "politically moribund".

Kennedy defended his decision to back British troops in Iraq despite voting against the government and challenged the home secretary over his call for identity cards.

"Purely on civil liberty points, we do not like the idea of compulsory identity cards," he said.

"Who would be the nature of the people who would be most likely to be stopped and charged? Unfortunately all the indicators are that they are certain sections that are much more likely to be stopped because of their appearance or the shade of their skin."

In a lighter moment, Kennedy was asked by a delegate who in the Pop Idol and Fame Academy TV shows he had backed.

The Liberal Democrat leader had backed an entrant called Pete "because he reminds me of David Bowie".