Nigel Farage has said it will be "tough" for Donald Trump to win the US presidency after a tape emerged of him boasting about using his celebrity status to prey on women.
But he also appeared to cast doubt over claims Mr Trump sexually assaulted women, describing their timing as "quite strange".
The Ukip leader is a vocal supporter of many of Mr Trump's policies and has spoken at a rally for the controversial Republican presidential candidate.
But Mr Trump's bid has been plunged into crisis after a 2005 tape recording of him bragging to TV host Billy Bush about groping women and that he can "grab them by the pussy" because he is a celebrity.
Mr Farage told ITV's Peston On Sunday the revelation has seriously damaged Mr Trump's prospects of getting into the White House.
He said two and a half weeks ago he thought there were many "shy Trump voters, there are non-voters like with Brexit" who do not show up in polls but could take Mr Trump to victory.
Mr Farage said: "I thought two and a half weeks ago he would win.
"I think the Bush tapes have really damaged him and at the moment he's behind, he's not that far behind, there are still 16 days to go. It's going to be tough, but it's not impossible."
But asked if he believed claims by a number of women that Mr Trump sexually assaulted them, he was more guarded.
He said: "I mean we've had all these sex cases going on for years and some people are guilty as hell as others have their lives ruined when they're completely innocent.
"All I would say about these allegations is, why didn't they come out earlier? Why did we hear none of this during the primaries over the course of the last couple of years?
"I don't know any more than you do what the truth of it is but I find the timing of it really quite strange."