A form of mandatory national service would be brought back if the Conservatives win the General Election in July, Prime Minister Rishi Sunak has announced.

Young people would be given a choice between a full-time placement in the armed forces for 12 months or spending one weekend a month for a year “volunteering,” in their community, the Tories said.

The Prime Minister said the policy would help unite society in an “increasingly uncertain world” and give 18-year-olds a “shared sense of purpose”.

Opposition critics dismissed the plans as unserious, with Labour saying the pledge would never come to fruition and amounted to “another unfunded commitment”.

Teenagers who choose to sign up for a placement in the forces would “learn and take part in logistics, cyber security, procurement or civil response operations”, the Tories said.

The Prime Minister said: “This is a great country but generations of young people have not had the opportunities or experience they deserve and there are forces trying to divide our society in this increasingly uncertain world.

“I have a clear plan to address this and secure our future. I will bring in a new model of national service to create a shared sense of purpose among our young people and a renewed sense of pride in our country.

“This new, mandatory national service will provide life-changing opportunities for our young people, offering them the chance to learn real world skills, do new things and contribute to their community and our country.”

A Labour spokesperson said: “This is not a plan – it’s a review which could cost billions and is only needed because the Tories hollowed out the armed forces to their smallest size since Napoleon.

“Britain has had enough of the Conservatives, who are bankrupt of ideas, and have no plans to end 14 years of chaos. It’s time to turn the page and rebuild Britain with Labour.”

Liberal Democrat defence spokesperson Richard Foord MP said: “If the Conservatives were serious about defence, they would reverse their damaging cuts to our world class professional armed forces, instead of decimating them, with swingeing cuts to the number of our regular service personnel.

“Our armed forces were once the envy of the world. This Conservative government has cut troop numbers and is planning more cuts to the size of the Army.

“This would be far better spent reversing Conservative cuts to troop numbers.”