They are heavyweights of the academic world, trading metaphorical punches over the right to proclaim themselves the most influential scientific body in the country.

In one corner is Imperial College, with academics such as Professor Neil Ferguson who are able to claim they have the ear of the Government itself. In the other is Oxford University, led by scientist and author Professor Sunetra Gupta.

The two groups clashed last month when they produced starkly contrasting studies into the possible course of the coronavirus outbreak, with both papers spawning dramatic headlines.

The Imperial paper predicted that up to 250,000 people could die if stringent measures were not enacted quickly – a prediction Boris Johnson clearly took to heart in initiating the UK lockdown.

The Oxford paper flagged up the equally eyebrow-raising, if more reassuring, possibility that half of us have had the virus already.

What many in the scientific community know but the vast majority of the British public does not, however, is that the rivalry between these two eminent research groups goes back a lot further than the past few weeks.

It began 20 years ago when the leading lights of both groups worked together at Oxford and stems from a sexual smear that resulted in a senior academic, Professor Sir Roy Anderson, leaving to set up his own team at Imperial College in London.

In 1999, Prof Gupta, then already an established author, had been coming to the end of a five-year fellowship in Oxford University's zoology department. She applied for a readership and a panel was convened to decide the matter. It was chaired by Sir Roy, then a Linacre professor of zoology and a Government adviser on various epidemiological matters, who had worked alongside the 34-year-old.

The eight-strong panel voted to award her the readership by six votes to two – but further debate ensued during which, it later emerged, Sir Roy had suggested she was being supported by the head of the zoology department because she had had a relationship with him.

When Prof Gupta, who was married, found out about the slur, she was appalled and demanded an apology. With none forthcoming she asked the university to intervene, but at first got little traction. "It seems to me the university was trying to brush it under the carpet," she said later.