Really unthought-out.
OK, UK students can delay university/college a year, but what about the funding crisis that universities are in - do they just fill their places entirely with international students for one year? Actually LSE/KCL/UCL/Oxbridge would much prefer that as a permanent situation anyway. Maybe international students taking a UK university place and a graduate job should also do a year of national service for us (just joking, the government only wants their Yuans and Rupees).
What about academic exams that 18-year olds should be focusing on, including retakes.
Also a non-military non-mandatory version of this already exists - National Citizen Service. Just expand that and widen the social groups that it targets. My DC would have loved it but it really isn't aimed at them at all.
Plus, Tory minister on TV this morning saying there is no punishment for not doing it - well, it's not mandatory then, is it?
The fitness and health assessments to join the military now are quite stringent, so why would you enlist a load of teenagers with variable fitness and health to join in with those who have had to undertake fitness and health assessments? You wouldn't, it's just canon fodder if you are unfit and unhealthy, perhaps with undiagnosed health conditions, including cardiac defects.
And if Sunak really expects me to believe that his 2 lovely girls are going to be risking their lives on the front line in Ukraine and Gaza, I am not that stupid. USA, UK etc are full of rich young foreigners dodging the national service in their own countries, including Israel, Ukraine etc.
Lastly, 2.5billion cost. With a university funding crisis, schools underfunded, NHS underfunded, roads full of potholes, not enough teachers, relying on overseas staffing for our doctors and nurses, I can think of a lot more useful and beneficial projects for this spending.