Thousands of prospective troops are dropping out before completing Army training, with lengthy delays suspected of fuelling the trend, according to reports.
More than 100,000 people signed up to the British Army in the 12 months up to March 2017, but only 7,500 became soldiers, according to The Sun.
It takes an average of 300 days between a person's first contract with the Army to them becoming a soldier, the paper said.
The uptake in interest marks a high-point in recent years - having shot up from 58,000 attempts to join in the 12 months ending March 2016.
Former head of the Army General Lord Richard Dannatt told the paper: "I've heard of a number of people who have been trying to join the Armed Forces and got fed up at the length of time it takes.
"The system is too complicated, the Army knows the previous system was better and would like to go back to it.
"The reason why it's not being done is because it's too expensive."
It comes amid concern that the military is in the grips of a recruitment crisis.
Last year a study by former armed forces minister Mark Francois, which was commissioned by Downing Street, said all three branches of the military are "running to stand still" as they struggle to replace the numbers leaving.
The 7,500 new recruits remains below the 10,000 needed to join each year for the Army to maintain its strength.
An Army spokesman said: "The huge demand to join the Army is to be welcomed and our new recruitment campaign and fitness app means thousands of people are applying.
"We are working hard to speed up the process so recruits who meet our world class standards can start their training as soon as possible."