A team of Royal Marines based at RMB Chivenor has proudly marched through London, raising thousands for charity but narrowly missing out on setting a new world record.
The soldiers completed the gruelling 26.5 mile London course but crossed the line in Pall Mall just two minutes and 13 seconds outside of the four hours and 19 minutes required to take the record.
Prime Minister David Cameron, his wife Samantha and their children Nancy, Arthur Elwen and Florence waved the troops on their way from 10 Downing Street ahead of the challenge.
After finishing the march the team laid a wreath at the Royal Marines memorial in The Mall.
They were given a rousing send off just after 10am with a rendition of Jerusalem by the Military Wives Choir.
Wearing 40lbs of kit and carrying a weapon, their route took in some of London's most famous landmarks including the Houses of Parliament, Marble Arch, Piccadilly Circus and Buckingham Palace.
The troops trained hard for the event, co-ordinated by Captain Baz Colarusso, who is part of the Commando Logistic Regiment at Chivenor.
Meanwhile a second team of veteran Royal Marines completed a 16-mile charity run to signal the start of celebrations marking the 350th anniversary, in 2014, of the foundation of the Royal Marines.
Their route took them past the City of London and east to the Queen Elizabeth Olympic Park.
Former Royal Marine Commando Mark Ormrod, who was the first British triple amputee from the Afghanistan conflict, took part on a handbike.
He tweeted: "What a day, shook hands with the PM, the 1st Sea Lord, rode 17 miles around London and attended the Graspan memorial, now to the after party."
It is hoped the anniversary run and the record attempt will raise £50,000 which will go to the Royal Marines Association and Commando 999.