organisers of the White Horse Challenge, the sponsored walk around seven of Wiltshire's chalk hill figures, may switch support to another charity if Wiltshire loses its air ambulance.

Over the last two years, the challenge has raised £16,000 for the air ambulance but organiser Richard Edwards said the situation would be reviewed if the Great Western Ambulance Trust carried out its plan to have one air ambulance for the region based in Filton, near Bristol. He said: "If the air ambulance is no longer a Wiltshire charity, it will have an impact on whether local people would want to support it.

"We would certainly review the situation, as we did last year."

So far 20 teams have signed up to the challenge of visiting the White Horses at Devizes, Alton Barnes, Pewsey, Marlborough, Hackpen, Broad Town and Cherhill.

Walkers set off on the 55-mile challenge at 7.30am on June 7 from the police headquarters in Devizes.

The challenge continues on the next day and there is also a relay challenge, where team members each walk a shorter distance, a one-day challenge over half the route on either the Saturday or Sunday and a seven-mile family challenge between Cherhill and Devizes on the Sunday.

To enter visit www.whitehorsechallenge.co.uk or phone Monahans on (01225) 785520.