An Oxford college should place a sign saying “Sorry” around the neck of a statue of Cecil Rhodes, a senior academic has suggested in the latest row over the controversial monument.

More than 100 academics at Oxford University are refusing requests from Oriel College to give tutorials to its undergraduates following its decision not to remove a statue of the British imperialist.

They have also pledged not to assist Oriel College with its outreach work and admissions interviews, and they will refuse to attend or speak at talks, seminars, and conferences sponsored by the college.

It comes after Oriel College was accused of “institutional racism” last month after its governing body said it would not seek to move the statue of Rhodes from its position outside the building.

Robert Gildea, professor emeritus of modern history at Oxford and one of the signatories of the petition, said the boycott is a way of “putting pressure” on the college after many alternatives had failed.

He told BBC Radio 4’s Today programme: “One of the options offered by the commission was to retain and contextualise, so if the college put up a notice explaining who Cecil Rhodes was that would be fine.

“If the college put a placard around his neck at lunchtime today saying ‘Sorry’ that would also be fine.”

Prof Gildea added that sculptor Antony Gormley’s suggestion that the statue be turned round to face the wall is also a “very interesting idea”.

A statement from the boycott organisers said: “Faced with Oriel’s stubborn attachment to a statue that glorifies colonialism and the wealth it produced for the college, we feel we have no choice but to withdraw all discretionary work and goodwill collaborations.”

It added: “The collegiate university can only effectively and credibly work to eradicate racism and address the ongoing effects of colonialism today if all the colleges do so.

“Oriel College’s decision not to remove the statue of Cecil Rhodes undermines us all.”

Danny Dorling, professor of geography at Oxford who is another of the signatories, said: “Having your university associated with a statue of a racist is deeply upsetting and puts a smear on the whole university.”

But the academics have been criticised by Lord Wharton, chairman of the Office for Students (OfS), who said it would be “utterly unacceptable” if students were left disadvantaged.

He said: “Oriel College took a decision to retain the Rhodes statue after carefully considering all of the evidence.

“It would be utterly unacceptable if any ‘boycott’ of Oriel led to students, or prospective students, at the college being disadvantaged in any way.”

Tim Loughton, a former minister for children and families, told the Daily Telegraph: “This is academic blackmail by a group of academics who think their own political views should trump everyone else’s, and if they don’t get their own way then any innocent students who happen to fall within their boycott will become the victims.”

An independent inquiry to examine Rhodes’ legacy was set up in June last year after the governing body of Oriel College “expressed their wish” to remove the statue.

Announcing its decision three weeks ago, the college decided against removal, arguing that the timeframe and cost were “considerable obstacles”.

A statement from the Rhodes Must Fall campaign in response described the decision as “an act of institutional racism”.

Oriel College has been approached for comment.

It comes amid another dispute over a decision to remove the Queen’s portrait at Magdalen College in Oxford due to concerns over its “colonial links”.

Members of the Magdalen College Middle Common Room (MCR), which is made up of graduate students, overwhelmingly voted to remove the picture from their common room.

Prime Minister Boris Johnson is said to back Gavin Williamson’s criticism of the students, according to Downing Street, after the Education Secretary branded the move “simply absurd”.

He has since faced criticism from the University and College Union (UCU), which said the comments were a “distraction from the disastrous, systemic failings this Government has presided over in higher education”.

Barrister Dinah Rose, president of the college, said staff have received “threatening messages” over the controversy, and she defended students’ right to “free speech and political debate”.