AROUND 3,000 national and international competitors are expected to descend on Okehampton Camp this weekend for the Original Mountain Marathon (OMM).

The event will test each team of two's fitness, equipment and navigational skill and ability to traverse the rugged Dartmoor terrain over two days.

The ethos is to be totally self-reliant, carrying all equipment with no outside support or GPS. Mobile phones may be carried but used for emergencies only.

There are eight courses, with the elite teams running 90 kilometres over the two days, the equivalent of two marathons back-to-back, carrying equipment for an overnight camp and food.

Andrew Watson, principal access and recreation officer for Dartmoor National Park Authority, said: 'We expect that the additional numbers of visitors to the Dartmoor area over the weekend will give a real boost to local businesses and the organisers have been encouraged to source local food and services.'

Andrew Denton, OMM events director, said: 'We are very pleased to be able to use Dartmoor National Park, one of Britain's breathing spaces.

'For those for whom this is their first visit, I am sure they will return again. We are also grateful for the support of Lt Col Clark and his staff at Okehampton Camp.'

The Original Mountain Marathon takes place this Saturday and Sunday (October 30 and 31).