Labour have demanded a Whitehall investigation into the appointment of the prime minister's former campaign manager to a key government role.
Education Secretary Gavin Williamson on Tuesday confirmed Conservative peer Lord Wharton of Yarm will be the new chair of the Office for Students, the independent regulator of higher education in England.
But the handing of the role to the former Tory MP and minister has been criticised as "simply another example of cronyism".
Labour's shadow education secretary Kate Green has written to Cabinet Secretary Simon Case to ask him to look into Lord Wharton's appointment to the prominent education role.
"It seems to me that Baron Wharton has none of the statutory qualifications for this post, and both the higher education sector and the wider public will be deeply concerned that this is simply another example of cronyism, which undermines trust in public life at a time when it is needed most," she said in her letter.
"This will only be made worse by Baron Wharton's decision to keep the Conservative whip, bringing into question his ability to make independent decisions.
"At a time when it is vitally important for the public to have confidence in government appointments, it is extremely disappointing that they continue to appoint those with close ties to the Conservative party to public jobs without the necessary experience or credentials.
"In this case, it is particularly alarming that this appointment is being made during a pandemic in which students have been forgotten by this government and are being denied a full university experience, yet Baron Wharton admits he has no direct experience in higher education.
"Gavin Williamson and Boris Johnson must be up front about how this role was appointed and what measures have been put in place to avoid any real or perceived conflict of interest."
Ms Green listed a series of questions about Lord Wharton's relevant experience for the role, as well as asking whether it would be "appropriate" for the peer to resign the Conservative whip before starting the role in April.
Lord Wharton ran Boris Johnson's successful campaign to replace Theresa May as Conservative Party leader - and prime minister - in 2019.
Mr Williamson also played a key role in Mr Johnson's election as Tory leader.
Lord Wharton lost his Stockton South seat as an MP at the 2017 general election, but was handed a place back in parliament when Mr Johnson appointed him to the House of Lords last year.
The prime minister's list of peerages also included his own brother, Jo Johnson, a key Downing Street aide and a prominent Conservative donor.
The Cabinet Office confirmed they had received Ms Green's letter and would respond in due course.