Defence secretary Philip Hammond has promised a review into women serving on the frontline.

He said the review would take place in 2018 and look at the rules that allow women to serve in a combat role but not where the primary aim is to kill the enemy.

Women are barred from the infantry or the armoured corps as they would be likely to end up in close combat.

Hammond said the review would show that the military was open to everyone who could meet set standards. The Army still had an image of being the "last bastion of male chauvinism" despite the reality being "very different", he said.

"At a time when the Americans, the Australians, the Canadians, even the French - the Israelis, of course, for years - have women in their combat arms, this is something we have to look at again," he said.

He made it clear that women would have to meet high fitness standards to serve in combat. But what exactly is required?

woman soldier
Woman soldier cleaning her boots before the Trooping Of The Colour Getty Images

"Fitness is important for everyone, but it's especially important for soldiers," the MoD website says.

"As well as the health benefits that come with being fit, you also need to meet the physical demands of the job. The Army helps develop your fitness, but you will need to meet some basic fitness standards to check that you're ready to start your Army training."

During a two-day selection process, would-be recruits must lift a 40kg weighted bag to a height of 1.45m.

They must be able to carry two 20kg water containers over a 120-metre course in less than two minutes, do 44 press-ups in two minutes, and 50 sit-ups in two minutes.

They must complete a 2.4km run. Women wishing to join the parachute regiment will have to complete this in nine minutes and 45 seconds.

To join the SAS, potential recruits have to undergo a series of endurance tests, including a 40-mile march in 20 hours without stopping. Throughout, they have to carry a 60lb rucksack, a rifle and a full bottle of water.

At the end of the trek, recruits should still be able to run four miles in 30 minutes.

"SAS are tasked to the highest level and can operate in difficult and often changing circumstances, sometimes in the absence of guidance and within situations that have significant operational and strategic importance," the MoD says.

"The kind of individuals required to operate successfully in these circumstances are not found in abundance. The selection process for entry into SAS seeks to identify the qualities and potential of those suitable for service within SAS."