Seb Green, who was heading through Hull yesterday accompanied by his collie Flash, aims to be home in Weymouth by Christmas.

A prank nearly ended in disaster three years ago when Seb, then 15, and his friend took a boat from Weymouth Harbour.

They got stranded and he became stuck waist-deep in mud. The massive rescue effort involved two helicopters, lifeboats and coastguards.

Seb later got a six-month referral order from magistrates.

He said: "The magistrates' court already punished me but I want to make amends my own way."

The march has been three years in the planning and Seb – who has walked as much as 34 miles in a day – is ahead of schedule.

The 5,821-mile walk will take him to Whitby and Tynemouth and then to Scotland and John O'Groats, before heading back south, walking through Wales, to reach Land's End and The Lizard in Cornwall.

He has been offered overnight accommodation or somewhere to put up his tent.

Seb, who carries a hefty 25-kilo backpack and wants to join the Royal Marines, said: "It's been OK; there's been minutes when I thought about giving up but the good minutes outweigh the bad.

"Quite a few people have offered me accommodation whether it be a spare room or back garden. Overall I have been surprised by the generosity.

"But when I am walking through town centres I think people think I am a sort of vagrant."

He added: "I've learned not to take people at face value which is something everyone seems to do.

"Through meeting people that have offered me accommodation from the impressions you get when you first meet them to sitting down and talking with them your impressions change."

Details of the walk – which has already raised £2,000 for the Starlight Children's Foundation, which helps terminally-ill children, and the Dorset and Somerset Air Ambulance – are online at www.sebsodyssey.org.uk.