The service, which runs completely on donations, wants to raise £2 million this year so it can extend its operating hours and employ a full-time doctor - but must contend with the extra costs of doing so.

And fundraising manager Jo Payne hopes a lot of swimmers will enter the event at Warwick School on September 14 to provide the charity with some of the cash it needs.

She said: “We want as many people as possible to put teams in because the more money raised the better for each charity. Last year we spent only nine pence in every £1 on things other than flying - so 91 per cent of our funding goes towards saving lives.”

Mrs Payne explained that the cost of fuelling the service’s helicopter had gone up from 29 pence per litre in 2006 to 69 pence per litre this year and that the total annual cost for 2008 could be more than £230,000.

She added: “We want to extend our hours so we will have to pay to lease it for longer periods - we also want to fund a doctor so that there is always one on board.

“ We are going out between five and 12 times a day and we want to continue to provide that service.”

The Air Ambulance have entered a team called the Sky Meds into the swimathon and have also arranged a fundraising abseil which takes place at the Coventry Hill Hotel on July 19.

Those who wish to take part in the later event, which costs £25 to enter, can contact Mrs Payne by emailing jo@wnaa.co.uk.

This is the 11th year running that the Soroptimists of Leamington and Warwick have organised the swimathon.

All the money raised will be split evenly between three charities, which also include the Physically Handicapped and Able Bodied Club and Relate’s Time For You counselling team, selected by the international women’s organisation. Teams of six swimmers and a non-swimming captain can enter by phoning the booking officer on 07880 987300 or emailing gab27@yahoo.co.uk.

Donations can be made by using the form below.