If you haven't heard of Alastair Humphreys, you should. After he finished university, Alastair didn't have a job so he set off on his bike and ended up cycling around the world. No training, no money, nothing. It took him four years.

Now he's travelled to all corners of the world - cycling across Siberia, rowing to France with a paralysed soldier and running the Marathon des Sables (finishing in the top ten Brits despite breaking his foot en route).

"Bread and ketchup for lunch near Junction 6  - living the dream!"

He's quite rightly earned himself the title of National Geographic Adventurer of the Year.

He's now started something he calls "microadventures". The idea is anyone can have an adventure - even if you live in London and only have 24 hours to spare. You just need a bit of imagination.

Which is why Alastair and his friend Ron decided to hike the whole way round the M25. Yep, the permanent traffic jam known as London's ringroad motorway. It's 118 miles long. They had eight days to complete it.

Alistair's mate Ron en-route around the 118 mile motorway. Photo: Alistair Humphreys

Alastair wanted to know whether people of Britain would be as kind as those he'd encountered in Siberia. Would they offer shelter for a night? Or even just a cup of tea?

Listen to the talk above to find out. You can read the full story here or read the Tweet-ened version here. Trust us, it's very entertaining.

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