Tens of thousands of runners including a Princess and an assortment of celebrities, cartoon and comic book characters gathered in the pouring rain today for the start of the London Marathon.
Up to 36,000 athletes are expected to finish the 26.2-mile course after pounding through the streets of the capital to earn their marathon medals and raise money for countless charities.
At the start line celebrity chef Gordon Ramsay, running his 11th marathon in 11 years, said he was "nervous and excited".
Standing with his wife, Tana, who is also running, he said: "The weather is perfect for the start. Not too hot, which is brilliant."
He said his wife had run three half marathons in three weeks, adding: "I feel for the first time in 10 years I'm going to get my arse kicked."
TV presenter Jenni Falconer, who is hoping to finish in three and a half hours, said she would prefer it to be hot.
"I'm getting very nervous," she said.
"The rain is coming down so it's not a good start."
Fellow GMTV presenter Lorraine Kelly said: "I'm really nervous about it. I'm just going to do my best. I'm determined to do it so fingers crossed. I don't know how long it will take. I'm just hoping to get around."
Princess Beatrice, 21, is aiming to become the first royal to complete the route as she joins a "human caterpillar" of 34 runners.
The team will be strung together two by two with bungee cords in an attempt to beat the record for the most people to finish a marathon while tied together.
Ahead of the event, the Princess, who is running for Children in Crisis, said she was "very, very excited".
The caterpillar is headed up by Virgin boss Sir Richard Branson's children, Holly and Sam. And this year Virgin has taken over sponsorship of the event for the first time.
As the rain stopped, Hollyoaks actor Ricky Whittle said: "The nerves are settling in now, this is it.
"I can't run away from it, or at least there's only one way I can run.
"It's going to be fun and we are all raising lots of money for a great cause."
As well as the celebrities, thousands of fun runners were set for the challenge.
Carole Furmanski, 54, an IT manager from Ifield Wood, near Gatwick, was taking on the course with the aid of her walking stick.
Ms Furmanski, who had a botched hip replacement operation in the summer of 2008, said: "I decided to do it for Scope, they do so much for disabled people and I know a little bit about what that's like now.
"I couldn't walk properly for a few years.
"My aim is to finish hopefully today."
At the celebrity start line British 400m record holder Iwan Thomas was at the front of the pack.
Those in fancy dress included a banana, tiger, lion, fireman, beer bottle, giraffe and several leprechauns.
Sir Richard, wearing a colourful pair of butterfly wings, ran alongside the human caterpillar.
His children, Sam and Holly, led the 34-person team, wearing luminescent green tutus, with Beatrice in the second row.
A total of 74 runners are taking part in 41 different Guinness World Record attempts, including fastest cartoon character, animal, superhero, alien and runner on crutches.
George Bingham, 49, from West Yorkshire, was wearing a 1/12 scale model of the Angel of the North.
He was hoping his costume, which is 14ft 1in (4.3 metres) tall with a wingspan of 14ft 9in (4.5 metres), would win him the record of tallest costume while raising more than £40,000 for charity.
He squatted down as he passed the start line so the model would fit under the starting arch.
Former Army Major Phil Packer, who sustained serious spinal cord injuries in 2008, set off at 10am, aiming to complete the route in 26 hours for 26 charities.
The ex-serviceman, who last year took 14 days to complete the course, has raised a total of £1.3 million for charity.
Other runners hoping to raise awareness for their charities included Ann O'Connor, 55, who was wearing a rhino suit for Save the Rhino.
She chose the charity after inheriting a rhino horn from her grandfather.
She thought it was probably almost worthless but it was valued by the BBC's Antiques Roadshow last summer at £15,000.
And Ms O'Connor, from Guernsey, who works for the Financial Services Commission, is now using the money to support the charity.
Before putting on the 12kg rhino suit, she said: "I've got a knackered knee, I've never run in my life, I just hope to limp over the finish line."
Thomas Gainard, 25, was wearing a 17kg donkey suit for Spana, a charity raising awareness for working animals.
He said the suit included everything a working donkey would wear during an average day, adding: "We only have to do this once but working animals have to do this every day of their lives.
"I've been waiting to do this for weeks with great anticipation. I'm just looking forward to getting my hooves on."
Russian Liliya Shobukhova won the women's race in a time of two hours, 22 minutes.
Last year's runner-up, Briton Mara Yamauchi, came home in 10th, four minutes, 16 seconds behind.
She told the BBC it was a "combination of the journey here and having been injured last year".
She said she "can't stand it when athletes reel off a lot of excuses" but she had not been as well prepared as she would have liked.
Yamauchi's 6,500-mile journey from her training base in Albuquerque, New Mexico, took six days because of the volcanic ash.
Ethiopia's Tsegaye Kebede, second last year, dominated the men's race, finishing in two hours, five minutes and 19 seconds.
Andy Lemoncello was the first British man home, finishing eighth in two hours 13 minutes and 40 seconds.
London Mayor Boris Johnson, who was cycling along The Mall, said: "It's been a fantastic day. There are 37,000 people here which is a great tribute to the organisational powers of the London Marathon.
"We've had a rubbish few days and weeks with the tourism in London because of this crackers no-fly zone."
He said the city was now "open for business" and London was "fantastic value".
Asked if he was interested in running the marathon himself, he said he was "tipping the scales at 16 stone", adding: "I'm always tempted but I'm very prudent in these matters."
Presenter Jenni Falconer missed her target time of three hours 30 minutes by just one minute.
She said: "I'm just really pleased to complete it. The last few miles were a real killer.
"I dread to think what my facial expression was like."
She said it was "such a good atmosphere", adding: "The crowds at the London Marathon are incredible."