The UK Government has approved the early phase of design of the Initial Gate submarine that will deliver the nation's nuclear deterrent into the 2060s, Defence Secretary Liam Fox has revealed.
He added, "the continuous at-sea deterrent is the ultimate guarantee of our national security and for the past 42 years the Royal Navy has operated continuous patrols to ensure just that.
"We do not know how the international environment will change over the next 50 years and we cannot dismiss the possibility that a direct nuclear threat to the UK might emerge."
The new submarines will replace the existing Vanguard Class and will be powered by a new nuclear propulsion system, the pressurised water reactor 3.
UK director of submarines Rear Admiral Simon Lister said that the new reactor was a robust, highly controlled system that will deliver further improved operations and low costs over its extended life.
The approval of the early phase of design ensures increased detailed design work and order for long-lead items will be undertaken to deliver the first submarine in 2028.