Last summer I rode Blue Marine Foundation's Solent Wave - 130 km from London to the south coast, raising funds to restore the seagrass meadows, saltmarshes and seabird colonies of the Solent, home to the UK's first seascape-scale restoration project. It was one of my best days on a bike all year, and it left me wanting to do more for this charity.

This September the riders go again: Blue to Beaulieu, London to the New Forest, funding Blue Marine's Sussex Kelp Recovery Project. One problem - it falls in the same week as the Copenhagen Half Marathon, and I'll be on a start line in Denmark instead.

So this year I'm doing my miles on foot. 21.1 km through Copenhagen, chasing 100 minutes, and raising money for the same cause the riders will be pedalling for back home.

Why Blue Marine? I've spent my life around the sea. The ocean is the world's largest carbon sink - but overfishing is dismantling its ability to stabilise our climate. Blue Marine fights back with real, measurable work: creating marine protected areas, restoring habitats like the Sussex kelp forests and the Solent seagrass, and building sustainable models of fishing. They've already helped protect over 4.8 million square kilometres of ocean, and their fundraising challenges alone have put more than £2.5 million into conservation. I can't add wheels to that this year - so I'm adding legs.

Every pound lands somewhere real. £5 can fund ocean education for girls in the Maldives. £10 sponsors a kilometre of my race - pick your kilometre and I'll carry you through it on race day. And if you're a UK taxpayer, Gift Aid adds 25% on top at no cost to you.

Thank you for backing me. Training updates to follow - and a sweaty, happy photo from Copenhagen in September.