Teenager fund-raiser Callum Fairhurst is gearing up for his biggest challenge to date – a cycle trip around the world.

The event, which begins in July, will see Callum cycle across dozens of countries and clock up 18,000 miles as he bids to raise tens of thousands of pounds.

Callum, 17, from Soham, announced the feat on Thursday, on what would have been his brother Liam’s 20th birthday, adding a special poignancy to the occasion.

Liam died after a battle with cancer aged just 14 in 2009.

Liam became the figure head for many charity campaigns and, at the time of his death, raised more than £340,000 for children with cancer.

Callum said: “This is a massive task, the biggest I think I have ever undertaken. I am not going to be sitting on a bike somewhere in a gym doing it, I am going to be going out to all the places that I have wanted to visit and cycling 18,000 miles.”

Callum’s challenge starts in Australia just 10 days after he completes his A level exams at Long Road Sixth Form, in Cambridge, in July.

On route, the former Soham Village College pupil will be visiting a host of countries including New Zealand, Canada, Thailand, Singapore and the United States – as well as Europe.

He is hoping the feat, which will take more than 230 days to complete, will raise £100,000 for the Liam Fairhurst Foundation, Free the Children and Serious Fun, which all support disadvantaged children.

He said: “A few years ago I was on Twitter and a guy called Sean Conway was cycling around the world and I remember seeing his tweets and thinking ‘this seems really fun’.

“From that moment I had it set in my mind that my biggest challenge I wanted to do was to cycle the world and now, finally, it has come about.”

Callum’s dad, Mark, added: “Callum has come on in leaps and bounds over the years. He has put an immense amount of effort into it and both myself and his mum are very proud of him and are very pleased with the way he is going.”

To find out more about the challenge, or to donate, visit www.justgiving.com/worldcycle or www.callumfairhust.com