TWO brave siblings will embark on an unusual summer adventure later this month, as they cycle 140 miles balanced on not two wheels, but one.

Callum and Elspeth MacKellar from Gunnislake, will be undertaking a fundraising challenge to cycle from Whitehaven on the West Coast, to Tynemouth on the East Coast in just four days — on unicycles.

Callum, 14, and Elspeth, who will turn 18 during the challenge, will be joining ten other unicycle fanatics from across the country in the adventure to raise money for the British Heart Foundation.

The pair are part of a unicycle club in Calstock.

Callum said: 'The club's been going for about seven years and I've been doing it for about five years. My sister got into it first and I saw her doing it and thought I'd give it a go. It's something different to do — whenever you do it in public, it turns heads.'

Callum said the unicycle community nationally is quite close knit and they are very active online: 'The leader of our club got an email about the ride and told us about it and we thought it was something we'd like to do.

'I don't think you can go into something this big without being a bit apprehensive, but it's not a race so there's less pressure on us.

'If you're good enough on a unicycle there is no reason why you shouldn't be as safe as a cyclist on two wheels — you have to be reasonably confident on the unicycle to even think about doing something like this.'

The youngsters hope to average 35 miles per day, cycling along the cycle path Wainwright's Way, passing through the Pennines and the Lake District. They are currently training for the mammoth task.

Callum said: 'We have been training a bit, but a lot of people doing it have been training for months. We've been training by going out covering long distances. So far the longest distance I've done is ten miles but I'm hoping to do between 14 and 18 miles before it.'

Their father, Pete, will cycle the journey with them on his mountain bike for support and to carry water and supplies.

Callum said he is hoping to raise around £300 for the British Heart Foundation, and Elspeth would like to raise as much as possible, as well as raising awareness of keeping fit and healthy to help beat heart disease.

Callum and Elspeth will start their one-wheeled adventure on Monday August 23 and hope to finish on Thursday August 26.

Anyone who would like to show their support for the siblings can do so by donating to their Just Giving websites at http://www.justgiving.com/elspethmackellar">www.justgiving.com/elspethmackellar and http://www.justgiving.com/callummackellar">www.justgiving.com/callummackellar