Ukip leader Paul Nuttall broke cover to launch an angry attack on his critics for waging an "evil smear campaign" by claiming he was not at the Hillsborough disaster.
The would-be MP also defended his failure to turn up at a Stoke Central by-election hustings earlier on Thursday, insisting he needed the time to write his speech for Ukip's spring conference, which starts on Friday.
Mr Nuttall has faced widespread criticism and calls to resign as an MEP after it emerged that a claim made on his website that he lost close personal friends in the 1989 footballing tragedy are wrong.
It came days after a report cast doubt over his assertions that he was at the match, at which 96 Liverpool fans were crushed to death.
Speaking during an election hustings on BBC Radio Stoke on Thursday, Mr Nuttall said the past few days have been "the most difficult circumstances I have ever been in in my life" and insisted voters can trust him despite the claims which have rocked his candidacy.
He said: "I have been a victim of a smear campaign, one which has been organised, one which tries to claim that I wasn't at the Hillsborough disaster even though I have provided witness statements.
"And the sources who said, 'oh he mightn't have been there' are unnamed, and they won't be named, and it's utterly disgraceful.
"There was a mistake on my website, which was put up by a press officer - I take full responsibility. It has now been taken down.
"I was there, I was at the game. I can prove I was at the game. And I think it is a very dangerous route for politics to take.
"Look, I thought I'd seen all lows in politics - this just isn't scraping the barrel, this is digging beneath the barrel."
His comments came just hours after he pulled out of a hustings organised by Stoke-on-Trent's City Centre Partnership business group, sending his political adviser and fellow Ukip MEP Patrick O'Flynn to speak on his behalf.
Challenged by his Labour rival Gareth Snell about why he was a no-show, Mr Nuttall said: "I was writing my speech for the conference tomorrow."
He added: "Because of the week I've had, and because of the situation I have found myself in, I had to juggle everything around.
"I had to ensure that I was in Liverpool on Tuesday and on Wednesday as well, and there is nothing I could have done about that, that's the circumstances I found myself in - the most difficult circumstances I have ever been in in my life.
"Part of it is my fault. The other part, the main part, the beginning of the story, was nothing but a very cruel and actually evil smear campaign."