Speaker Martin held office for nine years
Former Commons Speaker Michael Martin is to take a seat in the Lords despite a vetting panel expressing concern he could damage its reputation.
The Lords Appointment Commission raised concerns with Gordon Brown but was overruled, according to press reports.
The Commission declined to comment. It said its role was to vet choices but its advice to the PM was confidential.
Mr Martin was the first Commons speaker to be ousted in 300 years, over his handling of the expenses scandal.
By convention, Commons Speakers are elevated to the House of Lords on their retirement, where they sit on the non-partisan crossbenches.
The intervention by the appointments commission, chaired by the former Foreign Office permanent secretary Lord Jay, is understood to be the first time in the modern era questions have been raised about a former Speaker being offered a seat in the Lords.
Lord Jay is understood to have raised the committee's concerns in a letter to Mr Brown.
He is not thought to have recommended blocking Mr Martin's peerage, according to The Times, but did raise questions the committee believed should be taken into account.
The commission, which was set up in 2000, has a duty to warn the prime minister of the impact of any "public controversy".
In Mr Martin's case it was referring to his much-criticised handling of the Commons over the past year.
Mr Martin chose to step down as Speaker after facing a motion of no confidence from MPs angry about his handling of the expenses issue and unconvinced he was the right man to lead efforts to reform Parliament.
There was also concern about his decision to allow police to search the offices of Conservative MP Damian Green as part of an abortive leak inquiry.
By convention, Mr Martin has stood down as an MP, forcing a by-election in his Glasgow constituency.
Conservative MP John Bercow was elected by MPs to be his replacement as Speaker.
According to The Guardian, the Lords Appointment Commission referred to the terms of its vetting procedure in a letter to the prime minister.
It said the commission's role "is to advise the prime minister if it has any concerns about the propriety of a nominee".
It adds: "Propriety means ... the individual should be a credible nominee. The commission's main criterion in assessing this is whether the appointment would enhance rather than diminish the workings and the reputation of the House of Lords itself and the appointments system generally."
Downing Street said the decision to grant Mr Martin an honour, thought to be a peerage, was based on a recommendation from the House of Commons in an uncontested motion.
The news was announced by Labour whip Helen Jones, who is also vice-chamberlain of the household, before the start of Commons business on Monday.
She told MPs that the Queen had agreed to "confer upon the right hon Michael J Martin some signal mark of her royal favour".
The Commons had requested a peerage for Mr Martin in recognition of "his eminent services during the period in which he has, with such distinguished ability and dignity, presided in the Chair of this House".
Labour MPs are reported to feel Mr Martin deserves an honour for agreeing to resign to allow the Commons to reform itself after the expenses scandal but the move has provoked criticism from some Tory and Lib Dem peers.
Former Chancellor Lord Lawson told The Times a peerage for Mr Martin was a "mistake and unfortunate".
Liberal Democrat Treasury spokesman Lord Oakeshott criticised the archaic language in which the announcement was made.
He told The Guardian: "This is old-fashioned nonsense. Parliament should start using words that people understand and believe.
"Michael Martin should not be handed a P45 in an ermine envelope."