Four peerage nominations put forward by Boris Johnson have reportedly been rejected.
According to The Times, the House of Lords Appointments Commission blocked the applications.
The chairman of the independent body responsible for vetting potential peerages said that recent nominees had put his committee in an “increasingly uncomfortable” position.
Four Conservative Party nominations and one by the Democratic Unionist Party were rejected in the latest round of honours.
According to The Times, Lord Bew, who chairs the commission, believes that his committee is being put in an invidious position by party leaders proposing “unsuitable” candidates, even if they technically pass the propriety test.
Recent lists have included a string of controversial appointments, including Johnson’s decision to make Evgeny Lebedev, the Russian-born oligarch and son of a former KGB agent, a crossbench peer.
Under existing rules, the commission has an obligation to vet party political appointees for “propriety”, for example by checking that they are not subject to a police investigation or suspected of tax evasion.
They must also be assured that any appointment would not “reasonably be regarded as bringing the House of Lords into disrepute”.
The commission also looks at the credibility of individuals who have made significant political donations, loans or credit arrangements.
Earlier this month, 26 figures were made members of the House of Lords as part of the latest honours list.
Watch: Boris Johnson pulls out of race for 10 Downing Street
Tom Watson, Arlene Foster and former Tory MP Sir Nicholas Soames were among those set to enter the House of Lords. Other peerages that were approved include former Johnson supporters, MPs Jake Berry, John Whittingdale and James Duddridge.
Berry made headlines during the recent Tory party conference when he said that people struggling with their energy bills should either “use less or go out and get a better paying job”.
In 2020 Johnson was accused of cronyism after he gave a peerage to a former Conservative party co-treasurer Peter Cruddas in defiance of advice from the Lords Appointments Commission.
There have already been reports that Liz Truss could release her own resignation honours list after just 44 days in office.
Johnson had been tipped to attempt a return to Downing Street after Truss's resignation on Thursday, but he dropped out of the contest on Sunday and, on Monday, Rishi Sunak made history by becoming the first British Asian to be Prime Minister after Penny Mordaunt also failed to get enough backing to put her in the running.