Nick Clegg, the new Liberal Democrat leader, has vowed to "break the two-party system" in UK politics.
Mr Clegg was named Lib Dem leader in December
Speaking on Sky News' Sunday Live show, he admitted it would be "no small task" to reverse poll ratings which have Lib Dems on around 15%.
Mr Clegg also said he believed 2008 would be the "crucial year" to restore his party's fortunes.
His comments came as he finalised his frontbench team by announcing his full list of junior spokesmen and women.
The Lib Dem leader said the list of 22 frontbenchers formed a "strong team".
Mr Clegg was named party leader in December after beating Chris Huhne by just 511 members' votes in a two-month contest.
Beginning his first new year as party leader, the Sheffield Hallam MP said his message to the public was: "We are on the way to reinventing politics.
"The days of two-party politics are numbered."
He added: "I have set a very clear long-term objective which is that I want to see us over the next two elections break the two-party system for good, establish three-party politics for good."
Mr Clegg said his party had a "record of being credible and honest on issues which are unpopular and difficult for the other parties to deal".
He cited tax, immigration, civil liberties, the environment and Iraq war as examples of such matters.
"On all of the big issues which have dominated British politics in the last few years, we have been well ahead of the pack or we have been prepared to say things that the other parties haven't dared to say," Mr Clegg said.
"I think you will see more of that in the months to come."
The Lib Dem leader recently declared he does not believe in God and has insisted that he would always be prepared to give "clear and candid" responses to legitimate questions.
Discussing his willingness to declare his lack of religious faith, he said: "I think the days where politicians tiptoe round issues because they are considered to be somehow no-go areas politically... I think many people find that tantamount to evasion, which I think is something many people don't react to well."