Figures show more than 14,000 potential recruits were rejected from the army in 2017 on the grounds of medical restrictions.
But campaigners claim many of these men and women are perfectly fit to serve and their affliction would pose no threat to their performance in the field.
Sufferers of conditions such as eczema and nut allergies are automatically barred from enlisting, even for desk jobs.
Now a group of those affected by the rules are calling on Britain’s armed forces to relax their strict medical policy as a nationwide military recruitment crisis continues.
The Commons Defence Committee was told last year the army had a 5,500 troop shortfall from its target of 82,500.
Members of campaign group Right to Fight claim some of those “missing” troops could be found among thousands of applicants rejected each year for medical reasons simply by re-evaluating their recruitment policy.
Michael Wilson, 17, from Rutherglen in South Lanarkshire, jumped at the chance to join the army shortly after his 16th birthday. During the application process he was asked a series of medical questions and declared an allergy to nuts.
The teenager, who hoped to join the Royal Scots Dragoon Guards, said the allergy was so weak he did not even need to carry an EpiPen. “I think that rejecting people with mild allergies is absurd,” he said.
The army has insisted that all applications are considered on a “case-by-case” basis.