UK lowers threshold to bring reservists back into service in event of war

The UK will make it easier to call up tens of thousands of former military personnel, lengthening the period some are considered reservists and lowering the threshold to bring them into service if the country is preparing for war.

All former service members will be eligible to be called up for duty for up to 18 years after they depart, and until the age of 65, under changes to the rules announced by the Ministry of Defence on Thursday.

Currently, members of the Army and RAF who are a lower rank than officers are only eligible to be called up until they are 55, while the Royal Navy keeps people on standby for six years after leaving. Under the new system, the MoD will be able to draw on a far wider pool of former personnel for longer, as part of plans to strengthen the UK’s ability to mobilise at speed in a crisis.

The move comes as armed forces chiefs warn of the growing threat from Russia, although it may raise concerns over the impact on recruitment and retention if people fear they can be called back nearly two decades after they leave the armed forces. Some may also question how the policy will affect veterans who have moved into civilian careers, started families, or are managing long-term health conditions after service.

The measures will also mean reservists can be called up for “warlike preparations”, as well as “national danger, great emergency or attack on the UK”, in what the MoD described as a lowering of the threshold. The change reflects growing emphasis on readiness and resilience, as ministers argue the UK must be prepared for a wider range of threats, including escalation in Europe and pressure on NATO allies.

“The Army, Royal Navy and RAF normally respond to crises but our ability to win wars always depends on the reserves and wider society to generate mass quickly,” Al Carns, minister for the Armed Forces, said. “To win wars we need a whole-of-society approach including the economy and industry, and this move today is all part of that push.”

Veterans and reservists’ associations have been consulted on the changes, which will come into force from spring 2027. The MoD said it would continue to work with service charities and representative groups as the reforms are implemented.

The MoD is trying to implement the recommendations of the government’s flagship Strategic Defence Review (SDR), to modernise the armed forces and prepare for potential conflict. The review placed renewed focus on expanding the reserves, strengthening the “strategic reserve” of former personnel, and ensuring the military can scale up quickly if required.

But Air Chief Marshal Sir Richard Knighton, chief of the defence staff, said on Monday that the military faced an in-year budget shortfall and would have to make difficult decisions. The planned Defence Investment Plan that would flesh out the SDR has been repeatedly delayed.

“We can’t do everything we would want to do as quickly as we would want to do it within the budget that is set,” Knighton told MPs, and hinted that certain existing programmes could face curbs if the full SDR is implemented.

The SDR recommended that the regular army should not drop below its current size of around 73,000, and there should be a minimum of 100,000 regular and reserve personnel, with the ability to “rapidly expand and mobilise Reserve forces”. It highlighted the need to “invigorate the active and strategic reserves”, signalling a shift towards a larger, more flexible force structure designed to cope with prolonged and high-intensity conflict.