David Cameron has been accused by MPs of undermining public confidence in the honours system by awarding honours to five ministers sacked in his Cabinet reshuffle.
The Commons Public Administration Select Committee said the move flew in the face of assurances given by the Government and represented a further "politicisation" of the system.
Former ministers James Paice, Edward Garnier, Nick Harvey and Gerald Howard were recommended by Cameron for knighthoods after losing their jobs in the September reshuffle while Sir George Young - who has since returned to the Government as chief whip - was made a Companion of Honour.
In a rare step, the committee released a letter from its chairman Bernard Jenkin to the Prime Minister complaining that they were "perplexed and disillusioned" by his decision to make the awards.
Jenkin, a senior Conservative backbencher, said that they appeared "inconsistent" with evidence given to the committee by the head of the Civil Service, Sir Bob Kerslake, during its inquiry into the honours system.
"If it is the policy of the Government that the Prime Minister should retain the right to award honours at his personal behest, why was this not apparent from the Government's submissions to our inquiry?" he wrote.
"The honours you have announced may well reward 'exceptional service', but there is a danger that they will appear to the public to be political 'consolation prizes' for the ministers concerned."
In his reply Cameron insisted that he had only made a "very limited number" of awards, adding: "I am determined that these special cases will not affect the integrity of the wider honours system."
However, in its report the committee said the Prime Minister had effectively bypassed the new Parliamentary and Political Service Honours Committee which he had set up to vet such awards.
"Such a move does indeed constitute politicisation of the honours system and flies in the face of the stated position of the Government, as expressed only weeks earlier in oral evidence by Sir Bob Kerslake, the head of the Civil Service," it said.
"Without questioning the public service of those selected, by the Prime Minister, to receive honours at the end of their ministerial career, we are concerned that awarding honours in such a manner will further reduce public confidence in the honours system.
"Again, if the Government supports such political control of the award of honours in certain circumstances, it should be prepared to justify that."
The committee warned that the credibility of the Parliamentary and Political Service Honours Committee was also in danger of being undermined by the decision to include the chief whips of the three main political parties.
It said that their presence left it open to the charge of "political manipulation in the interest of party leaders".
"Whatever the Government's policy on honours is, they should stick to it. There is a lack of consistency between the evidence we received, and what happens in practice," Jenkin said.
"If honours are to retain any meaning and value they must be awarded to genuinely deserving recipients who have contributed to their communities above and beyond the norm, through a transparent system where people can see the value of the honour and what it was awarded for."