I hope everything goes swimmingly!

Ros Surtees, 49, will swim from the Firth of Clyde island Ailsa Craig to Girvan beach in Ayrshire on Saturday, a distance of about 10 miles, in freezing open water - a feat for which she has been training for more than two years.

As well as tackling the gruelling swim to mark her 50th birthday on August 26, she also hopes to raise £10,000 for Alzheimer Scotland A close family member is believed to have the devastating illness aged just 46, and now has severe memory loss, and Ros has been supported through the ordeal by the charity.

She said: "They have been fantastic and I realise what a lack of resources they have. They work on a shoestring.

"I have never done anything like this in cold water and I have never done such a long distance."

It could take between five and eight hours for Ros, from Stranraer, to reach dry land again, and because of the currents she is likely to have to cover up to 14 miles.

She will coat herself in grease - not to keep warm, she says, but to stop irritation caused by salty sea water - and will have a support team in boats and kayaks around her.

Ros first started swimming in the ocean when she lived in Hawaii 20 years ago.

Despite the low Scottish temperatures, she won't be wearing a wetsuit so she can register her swim with the British Long Distance Swimming Association.

She added: "I'm nervous but determined! The main thing is to enjoy it."

One person who has been offering Ros some advice is Maggie Hodgart from Kilmarnock.

She swam the same route in 1984 when she was 17, to raise cash for arthritis from which her mum suffered.

Maggie went on to become the second Scottish woman to swim the English Channel.

She did it in a time of 14hrs 16min in 1987, and in 1988 became the first Scottish woman, and one of only three women ever, to swim the Irish Channel.

Maggie, 43, who is now a swimming teacher, said: "I told her to get plenty of cold water training - and to look out for jellyfish!"