David Cameron has admitted he owes an apology to former Conservative party treasurer Peter Cruddas, who was made an "outcast" by the party after newspaper sleaze allegations.
Mr Cruddas was dismissed from the role after the Sunday Times reported that he was charging £250,000 to meet Mr Cameron but has since won a libel action against the newspaper.
High Court judge Mr Justice Tugendhat criticised the Prime Minister's response, saying he had subjected his former Conservative colleague to a "public humiliation".
Mr Cameron said he was "very sorry" about the treatment of Mr Cruddas, who claimed he was "cut off" by the party and "made to feel like an outcast" by the Prime Minister.
Mr Cameron said he was looking forward to meeting his former colleague later in the year.
He said: "I rather think I do owe him an apology.
"Had I known at the time how badly the journalists had behaved, I might have been in the position to take a different approach.
"I am very sorry about that. I congratulate Peter Cruddas on his victory and on the verdict he has won. I think it is very deserved.
"He has done a huge amount for this country. I look forward to meeting him after the summer."
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The High Court found the newspaper had falsely alleged that Mr Cruddas was charging £250,000 to meet Mr Cameron. The court also awarded him £180,000 in damages and ordered the newspaper to pay £500,000 in costs.
In his judgment, Mr Justice Tugendhat said Mr Cruddas had been subjected to a "public humiliation" by the Prime Minister, when Mr Cameron said in a speech in the wake of the Sunday Times report that what he allegedly said was "completely unacceptable and wrong".
"The Prime Minister did not know what Mr Cruddas had said. All he knew was what the Sunday Times had reported. This speech by the Prime Minister was a massive public humiliation for Mr Cruddas," said the judge in his finding.
Speaking after the ruling, Mr Cruddas said: "My world was turned upside-down when that article was published. I remember vividly having to walk into my offices the day after the article was published and face 500 of my staff, many of whom had a clip of the Sunday Times interview on their video screens. It was humiliating.
"I was also embarrassed to accept invites to events which meant that my charities suffered. The Conservative Party cut me off within two hours of the story breaking and did not want to hear my side of the story.
"I was constructively dismissed from my role as party treasurer and made to feel like an outcast as the Prime Minister and the party lined up to criticise me on television and radio. This hurt me immensely and further damaged my reputation."