BLOW... Philippa fell on Dartmoor (Image: nc)
She is the first woman to sign up to the 32-week Royal Marines Commando course in more than 350 years of the elite corps. It is understood Ms Birch was carrying a backpack weighing more than 70lb along with her SA80 assault rifle, when she stumbled and fell on the Dartmoor march. She is expected to face six weeks of rehabilitation before commanders will let her back on the course at their training centre in Devon.
Ms Birch, who joined the Royal Marines in March and has completed 10 weeks of training, is likely to join another rookie troop if instructors decide she is fit enough to continue.
She has profiled her journey on Facebook, calling herself Hannah Snell - a young woman who pretended to be a man to join the corps in 1745 and served in India, where she was injured in battle.
Ms Birch says she has a tattoo in honour of Hannah and has shaved her hair to cope with training.
The Royal Marines says no exceptions have been made for her on the course, apart from having her own room and shower area - which some suggest is psychologically harder because she has few people to talk to in the evenings.
In 2002, Major Pip Tattershall passed the short four-week All Arms Army Commando Course on her third attempt, but was prevented by the rules at the time from serving in a front-line combat unit.
Meanwhile, another woman recruit is attempting to complete the 16-month Royal Marines commando officer training course and of four women
