The Chief Of Defence Staff General Sir Nick Carter has raised concerns over whether young people understand the "notion of service", the Times reports.
Giving a speech at a defence industry dinner, the head of the UK's military, who took over as chief of the defence staff in June, spoke of the support the public has given to Britain's armed forces, but raised concerns about the future.
He said: "I think my generation understand the notion of service all too well, naturally recognising that freedom, without the commitment to service, without charity, duty, or pride in one’s country, is unworthy of our British values and unworthy of those who have died in their defence.
"I wonder though, whether the coming generation, who are less likely to have been exposed to military service, who obtain their information in a very different way, who have grown up in an increasingly complex world, in which attention spans are fleeting, and when there are proportionally more causes and charities vying for support, will still offer that same sense of support that our generation does to the armed forces."
In July, three-quarters of respondents to a nationwide survey felt that the minimum recruitment age to the British Army should be raised from 16 to 18.
In the UK, you can apply to be in the Army at 15 years and seven months old, being able to join at 16.
In February, Labour MP Madeleine Moon told the House of Commons that a "frightening" number of young people had no understanding of the armed forces.