A SIX-foot wall and 13 minutes are all that stands between a 5ft 8in Scottish girl and history.

Tomorrow morning Captain Philippa ''Pip'' Tattersall, a 26-year-old from Aberdeenshire, will make her final attempt to conquer two assault courses to become the first woman to win the coveted green beret of the Royal Marines.

She has successfully completed the other three tests which come at the end of Commando training for one of the world's most respected fighting forces and will try to overcome her toughest challenge, which proved too much for her earlier this week.

Yesterday, the nine-stone all-round athlete from Tarland successfully ''yomped'' 30 miles across Dartmoor, matching the 47 men in less than the required eight hours carrying full fighting order, safety equipment and weapons.

She had already successfully completed a nine-mile speed march and a demanding 70-minute endurance course at the Commando Training Centre at Lympstone, in Devon.

If she fails tomorrow, her third attempt to become a Marine, she will be given no more opportunities.

Carrying webbing weighing 22lb and a rifle, she will have just 13 minutes to complete the assault courses.

Pip will have to overcome more than a dozen obstacles on the first course, including the six foot wall, before moving straight on to the second course, named Tarzan, which is an aerial confidence test. It starts with a death slide, including obstacles high up in trees and finishes with a 30ft rope climb up a wall.

''Whatever happens all her family will be very, very proud of her to have got so far,'' said her mother, Jenny Tattersall.

Speaking at the countryside home near Tarland where Pip was brought up with her two brothers John-Clive, 30, and Richard, 25, Mrs Tattersall said: ''She's a tough cookie and if she sets her mind to something will do it.''

She admitted that the past week had been nail-biting as the family have waited on an almost daily basis for a call from Pip about her progress.

''It is the six-foot wall which she has had a problem with,'' she said. ''Just think about it. She is 5ft 8in, no more than nine-stones and she is carrying about 30lb on her back, and you see the

problem.''

However, Pip has completed it in the past. In her first attempt to become a Marine a year ago she failed on military skills but successfully completed the assault course prior to that.

She made a second attempt soon afterwards but had to withdraw with a back injury.

Applicants only get three attempts, whatever the reason for failure, so if she fails to scale the wall tomorrow her aspirations of joining the world's toughest fighting force will slither into the mud.

While Mrs Tattersall, her husband Clive - a retired oil industry engineer - and their sons would share her disappointment, they will still be proud of their daughter, a former pupil of Tarland Primary School. ''She is thoughtful, considerate and a lovely girl,'' she said. ''She is the best daughter any mum could have.''

After attending primary school in her home village, Pip went to a boarding preparatory school and then to Roedean before studying for a degree in sports science at Chester College at Liverpool University.

She then went on to officer training at Sandhurst and is a captain in the Adjutant General's Corps in Harrogate.

Although all the family are ''fairly sporty'' Mrs Tattersall admitted that she had ''no idea where it has all come from''.

''She is a go-getter who likes a challenge,'' she said. ''I think with the exception of skating she must have tried just about every sport.

''She started snowboarding with the army at the beginning of this year and within a couple of months was winning prizes. She has played hockey, rugby, swimming and is really an all-rounder.

''She comes home when she can but the army is her life and there are so many good things she can do like skiing and snowboarding - but I think she might come home after this little ordeal.

''I just hope she will still have enough energy for the assault course after all she has done. Because she did the nine-week course a year ago she was allowed to start at week five this time but that meant she had to get herself as fit as the rest by that stage.

''She got over the wall last year and she has managed it in practice and if you can do it once you can do it again - that's what I told her.''

Mrs Tattersall said her phone has been constantly ringing with John-Clive, a horticultural researcher in Kent and Richard, an oil industry worker in Aberdeen, asking after their sister's progress.

Two other female soldiers, Captain Claire Philips, 28, and Lance-Corporal Joanna Perry, 29, from the Royal Electrical and Mechanical Engineers, failed the commando course. A 26-year-old Royal Navy officer, Surgeon Lieutenant Katy Bray, also recently failed, dropping out in the fifth week, and now has 14 months to decide whether to make another attempt.

Although the Royal Marines are now in Afghanistan seeking out remaining al Qaeda and Taliban fighters, Pip will not join them on the front line if she does win her green beret.

Women who pass the Commando all arms course will be able to work in either combat support or combat service support areas of 3 Commando Brigade.

The battle to be a marine

There are four tests involved in the gruelling All Arms Commando Course.

Endurance: a 1.5-mile country endurance course over varying terrain with obstacles such as muddy pits and tunnels, followed by a four-mile run back to base and a shooting exercise.

Tarzan and assault courses:

swinging on ropes through trees and an assault course. The aim is to build confidence in operating at height.

Nine-mile march: speed march in a troop.

Thirty-mile march: in eight hours across moors, tracks and roads, laden with weapons, safety gear, and extra food and water.