Barrow submarines: Third Dreadnought class build starts at BAE

Dreadnought class submarines are due to come into service in the early-2030s

Work to build the UK nuclear deterrent programme's latest submarine has started.

The first steel for the vessel Warspite has been cut at BAE Systems' shipyard in Barrow-in-Furness, Cumbria.

It is the third of four new Dreadnought class submarines being built to carry Trident ballistic missiles at an estimated cost of £31bn.

Defence procurement minister Alex Chalk said progress was "crucial to maintaining our national security".

The milestone was a "significant step forward" in a programme that was "supporting thousands of jobs and apprenticeships across the country", he said.

It would be "protecting the UK and our allies for decades to come", he added.

Steel cutting marks the beginning of the submarine build

The government said the programme was one of the most complex engineering projects undertaken in the UK.

The four new nuclear submarines - Dreadnought, Valiant, Warspite and King George VI - will replace the Vanguard Class fleet in the early-2030s.

Work will now continue on Warspite, alongside the first two boats Dreadnought and Valiant.

Each is approximately 500ft (153.6m) long and contains 42km (26.4 miles) of pipework and more than 20,000 cables.

Defence procurement minister Alex Chalk met Barrow BAE staff at the steel cutting ceremony

Rear Admiral Donald Doull, Dreadnought's senior responsible officer, said the steel cutting was an "important step in the ongoing delivery of the continuous at sea deterrent".

Successfully constructing the new fleet was "a challenge that will take the determined effort of everybody with a responsibility for supporting the programme", he said.

BAE Submarines managing director Steve Timms called the steel cutting a "really significant moment for the thousands of employees here at BAE Systems and across the submarines enterprise".

Correction 21st February: This article originally reported that the estimated cost of the four new Dreadnought class submarines is £31m and has been amended to make clear that the figure is £31bn.