The 30-year-old, the All-Africa Games champion, was withdrawn from the race by the IAAF on medical grounds but then attempted to gain access to the Stadium here.

Video footage emerged of Makwala, one of the athletes struck by a bout of the norovirus, being denied entry to the dedicated athletes entrance by security.

Makwala was escorted back to the IAAF office on the Stadium site before he returned to the hotel.

He had earlier claimed he felt well enough to take part in the 400m final, where he was highly-fancied to take home a medal, after being forced to withdraw from the opening round of the 200m yesterday. 

Makwala, among 30 athletes and support staff to be affected by the outbreak of the sickness bug at the Guoman Tower Hotel, had been recommended by the IAAF to be quarantined for 48 hours "as per UK health regulations".

The quarantine is scheduled to end tomorrow at 14:00 local time.

These procedures were clearly explained to the teams following the outbreak, the IAAF claimed in a statement released after they were widely criticised for the way they had dealt with Makwala, who said he was "heartbroken" at not being allowed to participate.

The IAAF were heavily criticised on social media and by the likes of four-time Olympic gold medallist Michael Johnson.

The American said on the BBC that the IAAF had got it "horribly wrong".

The governing body insisted the decision to pull Makwala out of the 200m and then the 400m was made "on the basis of a medical examination conducted in the warm-up medical centre by a qualified doctor on Monday recorded in the electronic medical record system of the championships".

The IAAF added: "The team doctor, team leader and team physio had been informed following the medical examination that the athlete should be quarantined for 48 hours and would therefore be missing the 400m final on Tuesday."

These claims were disputed by Botswana Athletics Association head Falcon Sedimo, who told the BBC there had been "no medical tests at all" carried out on Makwala.

"It's just generalised assumptions because of the outbreak of sickness and he has just one of those symptoms," he said.

"There has been no official communication, no formal communication from the IAAF at all. 

"We found out from the media that he could not take part and he is heartbroken.

"I met Makwala this afternoon the indications were that he was ready and raring to go."

Makwala is the most high-profile athlete competing here to contract the bug, usually brought on by a bacterial or viral stomach bug and which causes diarrhoea and vomiting.

The three-time African champion played down his symptoms, however, and stressed he was "ready to race".

"I was not that sick," he said. 

"I just vomited. 

"Like any other athlete, I vomit. 

"I could have run because I did my warm-up well and I did everything well."

The Tower Hotel claimed this morning that they were not the source of the outbreak of the illness.

Members of the Botswana, Germany, Canada and Ireland teams - all of which have had athletes who have contracted the sickness bug - are staying at the hotel.

Some of the athletes have been quarantined at the hotel in a bid to stop the spread of the highly contagious disease.