The UK will build up to 12 new attack submarines, the prime minister will announce as the government unveils its major defence review on Monday. The review is expected to recommend the armed forces move to "warfighting readiness" to deter growing threats faced by the UK.

The Royal Navy is building 12 new SSN-AUKUS attack submarines, which are set to replace the UK's Astute class attack subs by the 2030s.

The UK intends to send a “message to Moscow” with plans to expand its fleet of attack submarines and invest in its nuclear deterrent as part of a new defense strategy to head off the threat posed by Russia.