In his first interview since the publication of Sir Gordon's report last month, Mr Greer says Sir Gordon has satisfied a lust for "heads" in an atmosphere that was "hot".
In the interview, which is to be broadcast on LWT's London Programme on Sunday, Mr Greer says Sir Gordon has left "a lot of questions unanswered".
Sir Gordon found evidence that Neil Hamilton had received cash payments directly from Harrods boss Mohamed Al Fayed.
Mr Greer, who was found to have misled a previous Parliamentary investigation into the relationship between lobbyists and MPs, said he was "delighted" that he and his now bankrupt lobbying firm had been cleared of acting as "a conduit" for Mr Fayed.
Mr Greer says in the interview that he is "comfortable" with the findings about him and argues that the original allegations that MPs received cash for specifically tabling questions were not proved.
But he says: "[Downey] is a distinguished civil servant, but he's not a judge; he's not infallible. He has ... arrived at a number of very surprising conclusions in his report." However, it would have "needed a man very much stronger than Sir Gordon Downey to have come down with a report that said: `No, I do not believe that Hamilton or anyone else behaved wrongly' because the atmosphere in which Downey prepared his report was ... hot."
He added: "The media and, indeed, I believe the public, wanted heads and Downey has supplied those heads."
Mr Greer also says he now sometimes regrets dropping his libel action against The Guardian, which had alleged he had arranged for MPs to ask questions in Parliament in exchange for cash and wishes he had never met Mr Fayed or taken him on as a client.
The lobbyist also denies operating a "slush fund" made up of payments from Mr Fayed for the purpose of paying MPs.
Sir Gordon concluded that "there is a strong probability that cash payments, additional to his consultancy fee, were made to Mr Greer, over a period of time ..."
The Commons Standards and Privileges Committee agreed earlier this month with Sir Gordon's criticism of four of the five former Tory MPs he censured - Sir Andrew Bowden, Tim Smith, Michael Brown and Sir Michael Grylls.
It has yet to reach a decision about Mr Hamilton, who has submitted a lengthy rebuttal and will cross-examine him under oath in the Commons at a televised hearing in October.Reuse content