A new missile defence system which will protect the Royal Navy's aircraft carriers has entered into service, the Defence Secretary will announce on Thursday.
Sea Ceptor, developed at a cost of about £850 million, can intercept and destroy enemy missiles travelling at supersonic speeds.
It will be deployed aboard the Navy's Type 23 frigates and is said to be able to deal with multiple targets at the same time, protecting an area of around 500 square miles over land or sea.
Defence Secretary Gavin Williamson, who will make the announcement at the Rusi Sea Power conference in London, said the system would "protect our nation against the intensifying threats we face today and in the future".
He said: "Fitting our warships with this ground-breaking technology not only protects our Navy but shows we are world leaders at sea.
"HMS Argyll will be the first ship to deploy with this cutting-edge system when she heads to support peace and security in the Asia Pacific region later this year."
The news follows successful trials and a test firing campaign which started last year, including from HMS Argyll off the coast of Scotland.
HMS Westminster and HMS Montrose, the second and third ships to be fitted with the system, have also carried out successful firings.
Sea Ceptor is being fitted to replace the Sea Wolf system on the Type 23 frigates.
The air defence system will be used on the new Type 26 frigates and Land Ceptor, which will replace Rapier for the British Army.
It uses MBDA's next-generation Common Anti-air Modular Missile (CAMM) as well as innovations in radar and datalink technology.
Richard Smart, director weapons for the MOD's procurement organisation Defence Equipment and Support (DE&S), said: "Sea Ceptor's entry into service with the Royal Navy is a significant milestone.
"It's really exciting to be delivering a new capability that will form part of the protection for the new aircraft carriers and will help to keep our service personnel and our country safe."
During tests from HMS Montrose, the system successfully intercepted a fast-moving drone target. Within seconds of the missile bursting from the ship's silo, the simulated threat was destroyed.
Commander Conor O'Neill, the Commanding Officer of HMS Montrose, said the system represented a "vastly improved capability" for the Navy, adding: "(It) puts us ahead of the game in being able to defend ourselves and our new aircraft carriers from threat."