Sacked former Tory Party chairman Nadhim Zahawi has apologised for failing to disclose millions of pounds in tax but said it was "careless, not deliberate".
The MP for Stratford-upon-Avon was sacked from his position in January after an ethics inquiry into the handling of his tax affairs found a "serious breach" of the ministerial code.
He is believed to have paid a penalty as part of an estimated £4.8m settlement dispute with HMRC.
Rishi Sunak's ethics adviser, Sir Laurie Magnus, found Mr Zahawi had "shown insufficient regard for the general principles of the ministerial code" as there were "omissions" to the government by Mr Zahawi regarding his tax affairs when he was appointed education secretary, then chancellor, then Tory chairman.
The prime minister sacked him as party chair following the inquiry findings but Mr Zahawi made no apology at the time for his actions, however, did say sorry to his family "for the toll this has taken on them".
But on Friday, as he faces growing disquiet from local Conservatives who are choosing whether to reselect him as their candidate in the next election, Mr Zahawi apologised for incorrectly filing his tax return.
"I think what was important was that Sir Laurie said that I cooperated fully and I was completely open, in fact I gave him access to my tax returns as a whole, and if the paperwork wasn't correctly filled in then I accept that and take full responsibility for that and I apologise for that," he told the BBC.
"The important thing I think is to make sure that I remind people that what actually happened was the assessment from HMRC was that it was a careless not a deliberate issue, it was something that I dealt with immediately and I accepted without argument the settlement that they put forward and I move forward from there."
Mr Zahawi said he "completely accepted the position of the prime minister" when Mr Sunak said he had to go.
He added: "But it is really important to focus now on the constituency and learn from the experience and hopefully make sure that I am as good a member of parliament as I can be for the people of Stratford."
The row surrounding Mr Zahawi had centred on a tax bill over the sale of shares in YouGov - the polling firm he founded worth an estimated £27m - which were held by Balshore Investments, a company registered offshore in Gibraltar and linked to Mr Zahawi's family.
Mr Zahawi had insisted he was "confident" he had "acted properly throughout".
He said he paid what HMRC said "was due" after it "disagreed about the exact allocation" of shares in YouGov.
The former minister added that the error had been found to be "careless, not deliberate" but has not disclosed the size of the settlement or whether he paid a fine.