Robert Kilroy-Silk has quit as leader of Veritas, the political party he set up ahead of the general election.
The former chat show host was facing a leadership challenge from disillusioned members but announced on Friday that he is to stand down immediately.
Kilroy-Silk, who is an MEP, said in a statement that it was clear from the general election result - and more recently from the Cheadle by-election - that it would be virtually impossible for a new party to make a significant impact in the current electoral system.
"We tried and failed," he said.
And Kilroy-Silk acknowledged that the party is struggling to be effective without a proper administration and substantial financial support.
The statement added: "In the circumstances I would be misleading the members of the party and the public if I pretended that we could make progress. We must face up to the truth.
"I would like to thank all those who have been part of our exciting adventure and to say how sad I am that it has come to an end so quickly."
But he added that he would continue to campaign on issues such as the EU, immigration, asylum and multi-culturalism, and he would still represent his constituents in the East Midlands as an MEP.
Veritas' acting chairman confirmed the leadership election will go ahead in the autumn as planned with the result expected to be announced in September.
