Rishi Sunak has said young people who serve with the military as part of his national service scheme will receive a “stipend” to help with living expenses.
The PM gave no details about the amounts of stipend, or allowance, participants would receive from the total £2.5bn a year budget.
The Conservatives have also confirmed “some form of sanction” would apply to those who refused to get involved.
Opposition parties have described the initiative as a “gimmick”.
The Conservatives have pledged that, if they win the general election, 18-year-olds will have to take part in a scheme involving military or civilian service.
The party has also suggested that incentives for young people to take up 30,000 military places could include highlighting national service on Ucas applications and urging employers to favour those who complete the placement.
Speaking to reporters at a campaign event in Buckinghamshire, Mr Sunak said: “This modern form of national service will mean that young people get the skills and the opportunities that they need, which is going to serve them very well in life.
“It is going to foster a culture of service which is going to be incredibly powerful for making our society more cohesive, and in a more uncertain and dangerous world it’s going to strengthen our country’s security and resilience.”
During a separate TikTok video, the prime minister said: “As is the case in other countries, we will provide a stipend to help with living costs for those doing the military element alongside their training.
“Meanwhile, on the civic side, we will make sure organisations have funding for training and administration.”
The party is continuing to use the social media site even though security concerns have seen its use on government devices banned.
Speaking to the BBC, Tory Party deputy chairman James Daly said there would “be some form of sanction” for those not taking part in the mandatory scheme.
“If you are fit and healthy and you are able to make a contribution to your wider community to do something for your area, I have faith that young people will take that opportunity,” he said.
But, he added, it was “important” to make the scheme mandatory “because this is about opportunity”.
Without a compulsory system and state support to create opportunities, “many kids will miss out and some of the kids who need this more than perhaps others in certain circumstances, are those who don’t have access to money, to have a parent who can organise a work placement or do something like this,” Mr Daly said.
The Conservatives said young people in full-time armed forces placements could gain better work or study opportunities, including fast-tracked interviews for graduate schemes in the civil service or private sector.
On Sunday, Home Secretary James Cleverly ruled out criminal sanctions for teenagers who refused to participate in any part of the scheme, saying: “There’s no-one going to jail over this.”
Foreign Office minister Anne-Marie Trevelyan told Times Radio the scheme would be compulsory in the same way as staying in education or training until 18 was.
Asked whether parents might face fines if their children refused to sign up, she said that would be an issue for the royal commission.
The announcement of the policy came as a surprise to many Conservatives, including some members of Mr Sunak’s own government.
In a post on X, external, Northern Ireland Minister Steve Baker, a former RAF officer, appeared to distance himself from the plan, suggesting it had been “developed by a political adviser or advisers and sprung on candidates, some of whom are relevant ministers”.
Under national service from 1947 to 1960, young men aged between 17 and 21 had to serve in the armed forces for 18 months – but it did not apply in Northern Ireland.
The Conservatives said a royal commission would look at the details of the scheme.
Last week – a day after the election was called – defence personnel minister Andrew Murrison told MPs there were no plans to reintroduce “any form of national service”.
He warned that, if national service military recruits were kept in separate units, “it would be difficult to find a proper and meaningful role for them”.
Campaigning in West Sussex, Labour leader Sir Keir Starmer described the scheme as a plan for a “teenage Dad’s Army” and a sign of “desperation”.
He also criticised the Conservative proposal to fund it “by cancelling levelling up and with money from tax avoidance that we would use to invest in our NHS”.
Labour questioned how the Ministry of Defence would fund 30,000 places for the scheme.
And pointing to cuts in the funding of the volunteer National Citizen Service in 2022 when Mr Sunak was chancellor, a Labour spokesperson said: “What were the flaws in that model of youth service which made it a bad use of money, that have been corrected in the new plan proposed this week?”
Liberal Democrat deputy leader Daisy Cooper said: “Not content with crashing the economy and sending mortgages spiralling, now the Conservatives want to fine parents whose children don’t take part in their hare-brained scheme.
“Rishi Sunak wants to clobber families with a National Service tax. It just shows the Conservative Party is totally out of touch and deserves to be kicked out of office.”
The Lib Dems called for cuts in army numbers to be reversed “to keep the country safe”.
