Pollard said: "This Labour government is now rebuilding our military, including through increasing the size of our strategic reserves and giving them more opportunities to work with their regular counterparts."

The Conservatives said their pledge would be to recruit approximately 18,000 new reservists to bring the total to 50,000.

The trained and untrained strength of the Army, RAF and maritime reserves was more than 32,000 on 1 January 2026, according to government statistics, external.

The Tories also want to ensure more reservists complete their minimum training days, which typically number 19 or 27 days.

A reservist who meets their minimum training commitment and also passes their military training tests currently receives a tax-free bonus payment on top of their pay.

The annual tax-free bounty was paid to 46% of reservists in 2024/25, according to the government, external.

Conservative Party leader Kemi Badenoch said Labour was "dithering", highlighting John Healey's decision to quit as defence secretary due to concerns that funding for the defence investment plan fell "well short" of what is needed to keep the country safe.

Badenoch said: "To fund our defence, Britain has to cut its welfare bill. That is why the Conservatives will restore the two-child benefit cap and use the money saved on defence.

"We will give our reservists a tax cut, backing our military to keep our country safe and ensuring we can boost our reserve forces to 50,000."

Cartlidge said the UK's Nato allies are boosting their reserves to "stand up to the more dangerous world we all face".

He said: "Britain must do the same, but whilst other countries have used conscription, we remain committed to a professional, volunteer armed forces - and that means we need to make reserve service financially worthwhile."

The Conservatives said implementing their policy would cost around £44m in the first year and this would increase across the five-year parliament.

Once the number of reservists reaches 50,000, the policy would cost an estimated £152m per year.

The largest cost would be associated with paying more reservists and the current ones serving on more days, with the tax-free incentive costing around £20m per year, according to the party.

Last year's Strategic Defence Review (SDR) outlined a shift towards "warfighting readiness" to deter threats and pledged billions in extra spending for extra ammunition, next-generation fast jets, drones, and new attack submarines.

It also anticipated it will "become necessary" to increase the UK's active reserve forces by "at least 20% when funding allows, most likely in the 2030s".

The SDR added defence "must make much better use of the resources available", including improving recruitment and retention, and welcomed some of the work being undertaken by the Ministry of Defence.