Mills told BBC Radio 5 Live’s Wake Up To Money that organisers should now be “making plans for a cancellation”.

On Wednesday, British Olympic Association chairman and former sport minister Sir Hugh Robertson said he was “very optimistic” the Games would take place.

“I’ve spoken to the IOC – everybody is working on the basis the Games will go ahead,” he told BBC Radio 4’s Today programme. “There’s been no talk of cancellation or postponement.”

On whether athletes will be vaccinated for the Olympics, he added: “It wouldn’t be appropriate to ask athletes to be fast-tracked. The BOA doesn’t want to queue jump, but this will look very different in the spring.”

Takaya told BBC Scotland’s The Nine that a decision on how many fans will be allowed inside venues in the light of the Covid-19 pandemic will be taken in March.

“We are not willing to see the Games taking place behind closed doors,” he said. “We obviously want to see as many spectators as possible inside the venues, which is why we have been working tightly with the Japanese government and all international stakeholders, spearheaded by the IOC.

“We will see in spring how we can accommodate spectators inside the venues. We also have to see what guidance we get from the government regarding spectators and look at the situation around sports, both internationally and nationally.”

Takaya also dismissed a recent survey which suggested 80% of locals want the Games cancelled or postponed, saying that it was just one of a number of such polls.

“Most recent surveys show people want the Games to be re-postponed, but in that trend we see that people are willing to see the Games go ahead in some form, which is why we want to keep conveying how we are able organise the Games in this situation,” he said.

Takaya said the Olympics could be delivered without mass vaccination, pointing out that “lots of sporting events are taking place in Japan” without one.

“Our counter measures on Covid-19 are working under the assumption that we will not have a vaccine, so even if we do not, our plan is that we will be able to deliver the Games,” he said.

“The J League and baseball season will start here very soon and there will be government guidance, so we will take all of those things into our considerations.”

Takaya was aware of the problems being experienced in Melbourne, where positive cases on three flights forced 72 tennis players into full quarantine before the Australian Open, with three players testing positive.

“We have been looking into many other sporting events that have already taken place in the last six or seven months,” he said. “The feedback has been invaluable for Tokyo 2020’s planning and we will put those into our considerations and further refine our counter measures on Covid-19.

“Athletes have been training very hard to pursue their Olympic and Paralympic dreams. We are very passionate about delivering the stage for those athletes this summer.”

Britain’s wheelchair tennis player and Paralympic medallist Gordon Reid, is preparing for the Australian Open. More than 70 players arriving into the country have to quarantine for 14 days because of positive coronavirus cases on their flights.

“It’s been really eye-opening here in Melbourne to see and hear the amount of logistical challenges and the scale of trying to organise just a tennis event in the current situation,” he said.

“You’ve got to multiply that by a thousand when it comes to the Olympics and Paralympics because they are on another scale. I’ve been speaking to Shingo Kunieda, one of the Japanese tennis players who lives in Tokyo, and he told me he thinks there’s a 50% chance the Games don’t go ahead now.

“Globally, the situation is getting worse in some places rather than better, so all we can do is hope they find a way to make it happen safely.”