Boris Johnson has condemned criticism of the appointment of free school pioneer Toby Young to the board of the new universities regulator, describing him as the "ideal man for the job".
In a tweet, the Foreign Secretary insisted Mr Young would bring "independence, rigour and caustic wit" to the role.
The Government has defended the appointment to the board of the Office for Students (OfS), arguing the writer's "diverse experience" will be beneficial in the role.
There have been questions raised about the Department for Education's descriptions of Mr Young's experience.
The Guardian newspaper said it had been told on Monday that Mr Young's "diverse experience includes posts" at Harvard and Cambridge.
But Mr Young later clarified that while he did teach students at the institutions, these were not academic roles.
"I taught undergrads at Harvard and Cambridge and was paid to do so but these weren't academic 'posts' and I've never made that claim," he told The Guardian.
In a statement, the DfE later said: "Toby Young's diverse experience includes time at Harvard and Cambridge as well as co-founding the successful West London Free School.
"This experience will be vital in encouraging new providers and ensuring more universities are working effectively with schools."
Among those to speak out against Mr Young's appointment was Sally Hunt, general secretary of the University and College Union (UCU), who said: "If this organisation was to have any credibility it needed a robust board looking out for students' interests.
"Instead we have this announcement sneaked out at new year with Tory cheerleader Toby Young dressed up as the voice of teachers and no actual representation from staff or students."
In reply, Mr Young tweeted:
Mr Young replied to the tweet:
In an interview for the Spectator Coffee House podcast, Mr Young said he was "tangentially qualified" for the role, due to his work on areas such as widening participation in higher education and setting up new state schools.
He suggested the reason there had been "such a fuss" about his appointment was "because I'm an outspoken Tory and defender of the Government's education reforms".