They lived up to classic expectations - the Four Knights running this year's Virgin London Marathon in pursuit of Lady Guinevere and, more importantly, to raise awareness for the British Heart Foundation, arrived in shining armour for their photocall alongside the Thames and Tower Bridge today.

The four Cameron brothers, Duncan, Angus and twins Hamish and Dougal, and their leading lady Amy, attracted a strong crowd of photographers and journalists to hear about their aim to raise £10,000 for BHS in memory of their father who died of a heart attack in 2004.

"Running the marathon is a great legacy for our father and a great way to raise awareness for a great cause," explained Duncan. "My father passed away two months before my first marathon, back in 2004, after suffering from heart disease for 22 years."

Duncan not only masterminded the family's plan to run this year's marathon but also designed and created their convincing full-bodied costumes, including helmets, shields and swords. "I'm a sculptor and artist by trade, so I carved our armour out of plaster casts and plastic," he said. "There's about 120 individual pieces."

Discussing possible complications from running 26.2 miles in fancy dress, Duncan added: "It's about movement. I reckon the costumes are the equivalent to running with a large bag of shopping, so it's not about weight in this instance. It's hard to see out of the helmets but the rest isn't too restrictive. Because the suits reflect light they're not too hot and are very visible, which is what we need to get people's attention. They're quite loud too as they rattle, parts of the shields are made from baked bean tin lids."

Duncan and Angus are more seasoned runners, with three London Marathons under their belts, while 2010 will be Hamish and Dougal's marathon debuts. "It's fantastic to actually be involved. I've watched the London Marathon three times as a spectator, supporting Angus and Duncan, and we all decided it would be a great tribute for all four sons to run together," Dougal said.

"We hope to get great weather, which looks promising, to bring out the crowds and get lots of cheers to raise as much awareness as we can for the British Heart Foundation."

And how did Lady Guinevere, who is Angus' girlfriend, take to being roped into the venture?

"Who could say no to running for hours in a lovely gown being chased by four men?" she said. "I've run a few marathons now and as a teacher I felt it was a fun opportunity to raise awareness for an important cause. And, it means so much to Angus and his brothers. I'm really looking forward to it."

The quintet vows to run the full course in roughly five hours and has raised over £5,000 of sponsorship so far. To add to their total visit their website: Knight Runners.