London - Amateur or 'fun' runners are often told, by way of encouragement, that it is an achievement in itself to have reached the start of a marathon.
But at this year's London Marathon, which takes place on Sunday, it is a sentiment that will be echoed by their elite counterparts.
The disruption to European airspace caused by a volcanic ash cloud created in Iceland left London organisers facing the nightmare prospect of losing most of their star names.
It was only thanks to an operation involving two special flights at a cost of 150,000 pounds that allowed the defending London men's champion Sammy Wanjiru and fellow Kenyans Abel Kirui and Duncan Kibet to arrive in Britain on Thursday.
Wanjiru, the reigning Olympic champion, set a London course record of two hours five minutes 10 seconds last year but fast times were far from his thoughts on Friday.
"I'm so tired," Wanjiru, who also won in New York last year, told reporters. "I'm a little worried now but after a good sleep I will start to look forward to it. I like running here."
Kirui, the reigning world champion, and Kibet will provide Wanjiru with a strong challenge as will Ethiopia's Tsegaye Kebede - last year's runner-up.
"If I don't win I think Kebede will, he's very strong and was second last year," Wanjiru said.
Predicted temperatures on Sunday of 21 degrees Celsius could work in the Africans' favour and hamper the hopes of their European rivals.
But hot weather is likely to be the last of Mara Yamauchi's concerns.
Last year's runner-up in the women's race, the Briton carries home hopes in the absence of the pregnant Paula Radcliffe.
Yamauchi, whose Japanese husband Shigetoshi is also her coach, has had a journey to London that makes Wanjiru's look like a short-haul flight.
Starting at her training base in Albuquerque, New Mexico, she travelled to Denver and flew to Lisbon before taking a 650 euros taxi to Madrid.
The Yamauchis then drove two days to Paris, only to be told there were no seats left on the Eurostar cross-Channel railway service.
They then took another taxi, this time from Paris to the northern French resort town of Le Touquet, from where they chartered a private plane that flew to Shoreham, on the south coast of England, before arriving in London after one last road journey.
As if that were not enough, Yamauchi finds herself up against a formidable opponent in Germany's Irina Mikitenko, who is bidding for a third straight London title.
Mikitenko's journey to London has been less convoluted than that of her British rival.
Both women have battled injuries since last year's edition and they each missed the August 2009 World Championships.
"I love running in London and I am determined to be fit and ready for the challenge, although I know it will be difficult against such strong opponents," Mikitenko said.
Meanwhile Yamauchi was not sure what to make of her unexpectedly lengthy trip home.
"It was very tough at points. There were times I thought we would not make it to London by Sunday, then there were also times I thought I would be the only person to make it to London and would win by 10 minutes."