OLYMPIC chiefs have been urged by Boris Johnson to end the uncertainty over this summer’s Games in Tokyo as more calls were made to postpone them until next year because of the coronavirus pandemic.

The Prime Minister’s spokesman said: “Athletes are facing significant uncertainty in the current environment. Their health and safety, alongside that of sports fans and officials due to work at the Games, must be absolutely paramount.”

He added: “We want the International Olympic Committee[IOC] to make a definitive decision soon to bring clarity to all of those involved.”

Nigel Huddleston, the UK Sports Minister, has already called on the organisers to “seriously consider” postponing the Games.

The pressure from Mr Johnson, who was London Mayor when the UK capital hosted the showpiece event in 2012, followed that of Lord Coe, Britain's most senior Olympic figure, who insisted that staging the Olympics in Tokyo in July was "neither feasible nor desirable".

Lord Coe, an Olympic gold medallist who is President of the International Association of Athletics Federations, told the BBC: “No-one wants to see the Olympic Games postponed but as I have said publicly, we cannot hold the event at all costs; certainly not at the cost of athlete safety and a decision on the Olympic Games must become very obvious very quickly.

"I believe that time has come and we owe it to our athletes to give them respite where we can," declared the Conservative peer.

He suggested the three areas of main concern were fairness of competition, risk of injury and the emotional well-being of competitors.

Lord Coe added: “We can no longer expect a fair and level playing field in our sport given the number of athletes, who are struggling to train in various countries due to measures put in place to reduce the spread of coronavirus."

Canada and Australia have decided to withdraw their teams from the competition; more are expected to follow suit.

Berit Kjoll, President of the Norwegian Olympic and Paralympic Committee, revealed she had advised its board "not to send any athletes to the Paralympics or Olympics in Tokyo 2020 in light of the serious situation".

Alejandro Blanco, Spain's Olympics chief, said he would prefer the Games to be postponed because the country's athletes were unable to train and that would result in "unequal conditions".

The British Olympic Association said it was now unlikely to be able to send a team.

As the pressure mounts even Shinzo Abe, Japan’s premier, has for the first time acknowledged postponement “may become inevitable”.

He told Japan’s MPs such a move would be unavoidable if the event could not be held in a complete way because of the coronavirus pandemic.

The IOC has said cancellation of the 2020 Games was “not on the agenda” but its Executive Board announced it would step up "scenario-planning" to look at the different possibilities open to it. A final decision is expected within four weeks.