If the UK were to introduce conscription in the event of a full-scale war, three groups in particular would be the first to be called up for military service, according to experts. Growing threats from Russia and China, coupled with NATO's Article 5 provision that an attack on one member means an attack on all, have put Britain on high alert for a potential large-scale conflict.
Order of Mobilisation
Retired senior British Army officer Lord Dannatt told the Express: "I would expect to see the Army Reserve mobilised first, then Regular Reservists recalled to active service and then His Majesty's Government would need to consider conscription, starting with 18-24-year-olds."
Anthony Glees, emeritus professor at the University of Buckingham, argued that full-scale conscription would likely follow the model used during WW2. He said: "This would mean that all males from 18-41 would have to do military or national service."
Historical Precedent
Glees noted that the WW2 model was decided in September 1939 when the UK declared war on Germany but before serious fighting had started, the so-called 'Phoney War' period. Previously, prior to the declaration of war in May 1939, all males aged 20-22 were required to do national service. In 1941, the age range was extended by ten years, so 18-51 and unmarried women were also required to do some kind of national service.
The professor believes the moment has come for the Government to start putting forward proposals for compulsory national service, with Ukraine potentially serving as a model.
Preparedness and Deterrence
Glees added: "We need a nation that is fighting fit and ready to fight but that doesn't necessarily mean 'with guns and bombs and bullets', it could mean using laptops and smartphones to push Russia back into its box."
He said: "We all agree we are already in a 'grey-war' situation in respect of Russia and that puts us in the 'Phoney War' context, in my opinion. Nothing would terrify that little coward in the Kremlin more than to see that the UK were taking the first measures to prepare for any tricks he may well have up his sleeve, especially now when Trump seems determined to let him have a win in Ukraine."
Glees pointed to Ukraine as an example: "When it was attacked, it introduced conscription for all males in the 25-60 year old category. Ukraine, with a population just a little more than half the UK's population, has armed forces of 900,000 men with a further four million in the reserve."
Volunteer Incentives
He insisted not all draftees would fight on the frontline, as many "could do useful defence work from their laptops." He cited an IPSOS poll showing that just 11% of 18-27 year olds say they are prepared to fight for their country, adding: "That's not bad, it's 154,000 brave young men. They would more than double the size of our army."
Glees suggested offering inducements to volunteers, such as release from student loan debts, assistance with study costs, even preferential housing. He noted that in WW2, soldiers were offered the prospect of 'homes for heroes' and a National Health Service, saying: "It was well worth fighting for these benefits. We need to do the same now."
In December 2025, the Government agreed to increase the number of young people going into the armed forces, aware that the UK has more traffic enforcement officers (82,000) than soldiers (74,000, although armed forces in total consist of 136,000 personnel). That measure was dismissed as 'baby steps'.
Mobilisation Challenges
The Royal United Services Institute (RUSI) indicates that reservists and ex-armed forces personnel would be prioritised for any recall, but highlights a significant challenge in tracking down and reaching former military individuals, alongside various other complications with large-scale mobilisation.
A research paper said: "With Russian military expansion and modernisation, and a growing rift between the US and European members of NATO, the risk of protracted conflict in Europe has grown. To deter such a conflict, or deal with the risk if deterrence fails, the UK's armed forces must be ready to mobilise and expand."
The paper added: "Policymakers and the public should be disabused of the idea that the UK's armed forces do not need to field a large force to match a potential enemy or adversary, nor that the UK can get away with leaving detailed planning until the event itself. The latest UK government's Strategic Defence Review has already implied greater mobilisation through its framing of the Russian threat, its commitment to the British Army providing a Corps to NATO, and the need to make use of the Strategic Reserve."
It warned: "This will not be easy given the current lack of preparedness for mobilising. Moreover, alliance cohesion requires burden-sharing, with all members sharing the costs equitably, which suggests that Britain must be better prepared to contribute mass. Preparing for this involves mobilising, training and equipping enough people, and that has implications for industry, which must also prepare for mobilisation."
To date, the Government has rejected the notion of conscription or compulsory military service. In September, Defence Minister Lord Coaker stated: "Since 1963, it has been the policy of successive Governments that the best way of providing for the defence of our country is by maintaining professional Armed Forces which are manned by volunteers."
Rather than enforced service, the Government is channelling its efforts into voluntary programmes designed to offer younger generations a taste of military life without committing to the regular Armed Forces. Lord Coaker added: "Through this combination of military experience, engagement, education, skills development and voluntary service opportunities, defence is already helping more young people understand the role of the Armed Forces, experience Service life, develop valuable skills, and explore opportunities to contribute to national security and public service."
