Growing instability in the Middle East and continued warnings over Russia's military ambitions have reignited debate over whether Britain could one day reintroduce conscription if a major conflict broke out.
Security concerns have intensified amid the war involving Iran and ongoing fears about the threat posed by Russia, prompting renewed scrutiny of the UK's military readiness.
Earlier this year, the Doomsday Clock was moved to 89 seconds to midnight, with scientists citing rising global tensions among the reasons for the change.
The Government has pledged an extra £15 billion for defence as part of its long-term spending plans, but some military figures argue more investment — and more personnel — may ultimately be needed.
Among those to raise the issue is former British Army officer and ex-MP Dr Mike Martin, who has previously argued that compulsory military service could become unavoidable if Britain became involved in a large-scale war.
Speaking to the Big Issue, he said: "Would we need to conscript? Yeah, we would. Because ultimately, we're not at a stage yet where you can replace people with drones.
"We're a long way off from that. Drones are fine, as far as they go, but you still need people to occupy villages, hold ground, and all the rest of it. And that's not going to change for quite some time."
Prime Minister Sir Keir Starmer has repeatedly said there are no plans to introduce conscription, insisting previously that "nobody is talking about" compulsory national service, reports London Economic.
However, the subject has remained in the political spotlight after former Prime Minister Rishi Sunak proposed a form of national service for 18-year-olds during last year's General Election campaign.
Former Chief of the General Staff General Sir Patrick Sanders has also warned Britain should be prepared for the possibility of mobilising civilians if the security situation in Europe deteriorates further.
If compulsory military service were ever introduced, there is no guarantee it would follow the same rules used during previous conflicts.
However, Britain's experience during the Second World War offers an indication of how mobilisation has worked in the past.
1. Young adults would likely be among the first groups considered. In 1939, men aged 21 and 22 were initially called up before eligibility was expanded to include those aged between 18 and 41.
2. Historically, unmarried people without children were generally conscripted before those with dependants, reducing the immediate impact on families.
3. Women could also play a significant role. During the Second World War, women aged between 20 and 30 were required to undertake war-related duties, including nursing, munitions work and other support roles, although they were not conscripted for frontline combat.
Whether women would be required to serve in combat roles today would depend on any future legislation, although a recent YouGov survey found strong public support for women serving on the front line.
4. Former members of the Armed Forces and military reservists could also be among the first considered because of their existing training and experience.
5. If a conflict became prolonged, eligibility could potentially widen further. By the later stages of the Second World War, men up to the age of 51 had become liable for conscription, while many older adults also undertook civil defence duties in support of the war effort.
