It is a departure from standards that might ordinarily drive sergeant majors into a fury.

But in the race to find cyber warfare soldiers to help wage hi-tech conflict, specialist recruits are being given a waiver from normal military regulations and allowed to have long hair, the Ministry of Defence has said.

Highly skilled cyber specialists are being granted individual exemptions from rules on appearance in an attempt to attract computer experts who may otherwise be put off from joining up.

The special measure is being taken because of the difficulties attracting much sought after “geeks” to the new cyber reserve which is critical for the military’s plans to wage war on the new digital front lines.

Commanders keen to recurit specialist expertise for 21st century warfare are also considering exemptions for reservist cultural advisers, linguists, intelligence analysts and criminal investigators.