Work is under way for the second ship in the Royal Navy's next generation of Type 26 anti-submarine frigates.
The first steel has been cut at BAE Systems' shipyard for HMS Cardiff, which marks the official start of the build on the second of eight City-class vessels.
All eight Type 26 frigates will be built on the Clyde, with the work sustaining some 1,700 jobs in Scotland and 4,000 jobs across the wider UK maritime supply chain for decades to come.
Defence Minister Anne-Marie Trevelyan said:
"These ships will clearly contribute to UK and allied security, but also make a strong economic contribution to the country."
Chief of Materiel Ships, Vice Admiral Chris Gardner, said it signalled a move to enhance "our naval capability for years to come".
Vice Admiral Gardner added: "Type 26 will form a key part of the Royal Navy's future balanced Fleet, providing a core component of anti-submarine protection."
The frigates will replace the current anti-submarine warfare Type 23 frigates and provide advanced protection to the Continuous at Sea Deterrent and Queen Elizabeth Class aircraft carriers.
They will also offer anti-submarine warfare capabilities.
Each Type 26 will be equipped with a range of capabilities including the Sea-Ceptor missile defence system, a five-inch medium-calibre gun, an embarked helicopter, medium-range radar, powerful bow and towed array sonars and helicopter-launched torpedoes.
Their design will also make them difficult to detect.
They will be designed for joint and multinational operations across the full spectrum of warfare, including complex combat operations, counter-piracy, humanitarian aid and disaster relief work.
The first three ships, HMS Glasgow, HMS Cardiff and HMS Belfast, were ordered for £3.7bn.
The first Type 26 warship, HMS Glasgow, will enter service in the mid-2020s. Designed for a service life of at least 25 years, the Type 26 frigates will serve in the future Royal Navy surface fleet into the 2060s.