The 26-year-old Paralympic champion is the first high profile name to definitely miss this year’s event because of the air travel chaos.

A spokesperson for the event said that strenuous efforts were being made to assemble all the elite competitors in time for Sunday’s race, but that no statements were being made until arrangements were definitely in place or competitors were definitely unable to make it.

"Our biggest problem at the moment is getting all the athletes to Europe," they added.

Fearnley, who was set for another almighty battle with the Briton whose winning sequence of three titles he ended in London last year, David Weir, had to accept this lunchtime that he was not going to make the trip in time from his home in Carcoar, New South Wales.

"I am feeling pretty gutted at not being able to come to London but there is nothing I can do," said Fearnley, who had planned to fly in directly from Sydney to London and was unable to find any alternative routes involving flights to Europe.

"I have worked really hard over the last eight weeks to be ready for this race and can’t believe it’s not going to happen.

"The London Marathon organisers have done everything they can to get me there but it’s just not possible. I will really miss being there but good luck to everyone else."

Fearnley, who broke the course record last year, is not the only Australian competitor to be stranded – his compatriot Christie Dawes, fifth in last year’s women’s race, has also had to pull out.

"We looked at every possible option for Kurt," a Marathon spokesperson said.

"Even though he has a close relationship with Qantas, they couldn’t find a way of getting him to Europe, even by flying first class.

"We looked at flying him to Dubai and trying to get him to Europe from there, but that didn’t work either.

"When I spoke to him today, he just said ‘I’m not going to be able to make it, am I?’

"He was absolutely devastated about it."

Virgin London Marathon race director Dave Bedford said: "We are very disappointed to lose our reigning champion.

"Kurt has raced here for the three years and we were looking forward to welcoming him back as champion and course record holder. Unfortunately, circumstances have conspired against us this time.

"However, despite losing Kurt and Christie both the men’s and women’s wheelchair fields remain top quality and we fully expect two thrilling races on Sunday."

Fearnley’s absence leaves Weir as favourite to win his fifth London Marathon title.

The Briton, who was London champion three years in a row between 2006 and 2008, was devastated to lose his crown last year.

Exactly who will be there on the day to challenge Weir is still not certain either, as ten of the leading wheelchair racers, including South African Ernst Van Dyk, the fastest man in history, are trying to find a way of getting over to London after competing at the Boston Marathon.

Others stuck on the other side of the Atlantic include Josh George and Adam Bleakney of the United States, Masazumi Soejima and Kota Hokinoue of Japan, Rafael Botello Jiminez and Roger Verdaguer of Spain, and Krige Schabort of South Africa.

Also there are Wakako Tsuchida, the Japanese athlete who won the women’s race in Boston for the fourth consecutive year this week, and London’s reigning women’s champion Amanda McGrory who was third.