'We're moving from a party of protest to a party of power. We're close to tipping point'

Charles Kennedy has warned the Liberal Democrats not to get "carried away" or "overstate the case" about their ability to form the next government. The Liberal Democrat leader moved yesterday to dampen expectations after one of his senior aides predicted that the party could seize power in five years' time.

Charles Kennedy has warned the Liberal Democrats not to get "carried away" or "overstate the case" about their ability to form the next government. The Liberal Democrat leader moved yesterday to dampen expectations after one of his senior aides predicted that the party could seize power in five years' time.

But Mr Kennedy said the party was close to reaching a "tipping point" in its fortunes, adding: "The chemical combustion is beginning to happen."

In an interview with The Independent, Charles Kennedy distanced himself from claims by Lord Razzall, who chairs the Liberal Democrat campaigns committee, that the Conservatives were "finished as a serious challenger for government in our adult lifetime". The Liberal Democrat peer also suggested his party could form a government "sooner" than 2010.

Mr Kennedy said he would never have made such a statement "because it is not my approach to overstate the case". He added: "I think there is a difference between someone like Tim [Razzall] saying that and someone in the position of a David Steel or me saying it."

Although he said it was a mistake to make predictions about when the Liberal Democrats would come to power, Mr Kennedy said there would come a time when Labour fell from office. He believes the Conservatives will not be the party that take over from Labour.

Mr Kennedy said: "The laws of nature dictate that there will not be a Labour government for ever and therefore, by definition, there will have to be something else. That 'something else' is not the Conservative Party, so, by definition, that must involve us."

In his speech to the conference today, Mr Kennedy will pursue the theme of the demise of the Tory party, which he will say has been driven from the inner cites, Scotland and Wales. He will tell delegates in Bournemouth that "in most of the country, to vote Conservative is a wasted vote".

Mr Kennedy will also declare that the Liberal Democrats are "moving from a party of protest to a party of power". Earlier this week, Mr Kennedy refused to rule out a coalition with Labour but said he would not "prop up" a failing government. Mr Kennedy said: "On any likely scenario the next side of the next election the Liberal Democrats will continue as an independent party in Parliament.

"If the issue is considered one worth exploring the other two party conferences are coming up: over to you, Mr Blair and Mr Howard."

But Mr Kennedy made it clear that voting reform, and a referendum on the introduction of proportional representation, may be a prerequisite for any kind of electoral pact.

He said: "What I would hope is that both the other parties increasingly see the merits of the need to revisit the whole voting system for the House of Commons and of giving the people a referendum and let them decide."

The Liberal Democrats were "getting close to the tipping point" where the party had critical mass as the third political force in Britain. Mr Kennedy said he was encouraged by the party's election successes in Brent East and Leicester South and that the newspapers were now talking about three-party politics.

The Liberal Democrat leader said the party was helped by the fact that people no longer had such fixed party allegiances and there was "a less defined political culture" in Britain.

"I will be saying that politics is a lot more complex than it was before. It isn't a left/right choice and you just vote Labour or Tory every time. You can be anti-war and pro less tax and less red tape and business regulation.

"Our approach is appealing to a less-defined political culture than there has been up to now. This is a generational thing."

Mr Kennedy said he was enjoying the conference and was very pleased with how the event was proceeding. But he added: "I don't want it to get too serious. We have to convey the sense that politics is about optimism. It's not just about getting depressed about the problems that face us. It's about being optimistic about the fact you have some solutions."

The party leader, sitting in his Bournemouth hotel suite, was in a relaxed mood as he discussed his party's prospects. But Mr Kennedy, who was known before he became Liberal Democrat leader as "chat-show Charlie", said he did not want to be seen as too po-faced.

Mr Kennedy, who will be preceded on stage today by a two-minute film highlighting his leadership, said he had not ruled out going back on the chat-show circuit and even appearing again on the BBC's Have I Got News for You.

He said he had heard that he had been booked, alongside Tony Blair and Michael Howard, on the comedy chat show The Kumars at Number 42 - although his press officer looked mystified at the suggestion.

Looking fit despite his gruelling 5.30am starts during conference week, Mr Kennedy said his secret was moderation in all things. "I am quite an enthusiastic walker. I am not talking about climbing the Monroes or anything ... I just eat well, sleep well and get on with it," he said.

But there is one more mountain to climb for Mr Kennedy - quitting smoking. He said the amount he smokes is "between me and my GP", but added: "That remains the 'Mount Everest' in my life. The lack of oxygen on this occasion is going to spur me on. I have reduced drastically. However, I have not yet reached the magic target of 0."

He adds, with a mischievous smile: "A Kennedy of 0 emissions - but not setting a target of 2010 - would be commendable."