HUNDREDS of people are expected to plunge into the waters off Plymouth to take part in a mile-long challenge designed to promote awareness of the marine environment.

Triple round-the-world yachtsman Conrad Humphreys yesterday launched the Blue Mile from Plymouth's Barbican, where he was joined by a team of elite water sports athletes who are "passionate" about promoting the "race for the environment" message.

Mr Humphreys said encouraging people to get in among the waves was aimed at helping them make the shift from awareness of the problems facing the sea, to taking action on the issue.

Activities at the event, supported by the Western Morning News, will include swimming, rowing, sailing and paddle-boarding, as well as beach games on sand to be brought into Plymouth Hoe.

On his voyages, the Vendee Globe sailor has witnessed the damage to the oceans at first hand, from discoloured waters to more floating icebergs as a result of global warming. He said: "It's great for sports people to be able to say 'we can be part of the solution' by encouraging others to do something about it."

He wants people to get into training for next summer now, and hopes they will fall in love with the sea in the process.

The team is working with Plymouth City Council and the South West Regional Development Agency to encourage as many people as possible to challenge themselves to a mile of activity on or near the water, over a weekend next summer.

Mr Humphreys harked back to his own inspirations, as a boy growing up in Exmouth.

The sea was on his doorstep but personalities such as Sir Peter Blake helped to spark his ambition, and he now hoped the Blue Mile will help spur others on.

He hopes the event will build year on year from the inaugural one in Plymouth, and will roll out across the country and the rest of the world in the run-up to the 2012 Olympics.

He said: "Plymouth has one of the best natural amphitheatres in the UK. This location is absolutely perfect for an event like this."

The mile-long course itself should help motivate participants, who will set off from the Mayflower Steps, where the Pilgrim Fathers are said to have left for America. It will then finish at the point where Sir Francis Chichester arrived as the winner of the first single-handed transatlantic race in 1960.

Yesterday, European longboard champion Ben Skinner, from Newquay, welcomed the chance to inspire others as one of the ambassadors of the "incredible" Blue Mile project.

The 24-year-old, who was en route to an international competition in Japan, remembered how world surf star Joel Tudor tutored him as a boy.

"I just wanted to be like him and become a world champion," he said.

"It's all about getting into the ocean and enjoying it for what it is, recognising that we need to keep it clean and respecting the fact that it provides us with an exciting and healthy lifestyle.

"After that, when you see someone throwing rubbish into the ocean, hopefully you will stop them."

To find out more, visit www.thebluemile.org