Ukip leader Diane James quits after just 18 days in role
She was voted in as leader last month with more than 8000 votes.
Diane James has quit as leader of the UK Independence Party.
The 56-year-old was voted in as leader last month with 8,451 votes, having fought off competition from Lisa Duffy, Bill Etheridge, Elizabeth Jones and Phillip Broughton.
In a statement, she said "I will not be formalising my my recent nomination to become the new leader of the party with the Electoral Commission.
"It has become clear that I do not have sufficient authority, nor the full support of all my MEP colleagues and party officers I believe necessary and upon which I based my campaign.
"For personal and professional reasons, therefore, I will not take the election process further."
This means that technically, Nigel Farage is still party leader.
The revelation that her nomination was not formalised has sparked debate that Nigel Farage would return, but he told the Press Association that he would not come back: "Not for ten million dollars."
Asked if he would take more money, he said: "No I'm not coming back, I'm retired."
According to one source within the party, many did not have confidence in James - they told ITV News correspondent Rupert Evelyn that she was an "accident waiting to happen"
James was favourite to win the post after Steven Woolfe was excluded from the race since he submitted his paperwork late.