A new submarine escape system could make the difference between life and death for sailors trapped underwater, the Royal Navy has revealed.

       The Nato Submarine Rescue System (NSRS), jointly owned by the UK, France and Norway, should shave “vital hours” off rescue missions.

       It is capable of diving down to a submarine in distress, docking with the escape hatches and carrying out an evacuation. It is designed to be transported anywhere in the world within 72 hours.

       Until now, the most time consuming element of any mission has been the need to weld the decompression chamber to a vessel conducting the rescue.

       Recent trials in the Baltic Sea and Liverpool Bay have perfected a new docking system that will enable much swifter action.

       British submariners said the new system gave them “a lot of comfort”. In the event of a catastrophic incident, “we know it’s there, it works and they will rescue us,” one said.

       The NSRS is housed at the Royal Navy’s Faslane submarine base in Scotland.

       How does the system work?

       The system consists of three elements - a remotely operated vessel to find a stricken submarine and clear debris from the access hatch; Nemo, a piloted miniature submarine, with room to rescue 15 submariners at a time; and a surface-based “transfer under pressure” complex.

       Rapidly connecting this directly to the deck of a rescuing ship could save many lives.

       The decompression complex is operated by diving and medical specialists from all three nations.

       The new system, trialled with the French ship Garonne, one of four new specialist Loire-class support ships, allows the decompression complex to connect to most commercial vessels.

       In the Baltic Sea trials, the Royal Navy’s rescue vehicle - called Nemo - conducted seven dives, and proved its ability to dock with a Swedish submarine.

       Further exercises with the French Navy in Liverpool Bay trialled the new docking system.

       A Royal Navy source said: “We continually seek to exploit opportunities to shave vital hours off any rescue.”

       Although NSRS is owned by Britain, France and Norway, Commander Richard Cragg said it would be “automatic” to assist other Nato nations in the event of an incident.

       The system would likely be offered to any other country suffering a disaster underwater. “If there was an incident and NSRS could help, I would expect it to be mobilised,” Cdr Cragg said.