The race to design and build a new generation of Royal Navy frigates has been won a consortium led by Babcock.
The firm has been named preferred bidder for the £1.25bn contract for five Type 31 warships.
The deal secures hundreds of jobs at Rosyth in Fife, where the ships will be assembled, with construction work spread between yards across the UK.
Work is due to begin by the end of the year, with the first ships delivered in 2023.
The Type 31 is a smaller, cheaper frigate than the Type 26 warships currently being built at the Upper Clyde shipyards.
With a price ceiling of £250m per ship, the aim is to maintain the size of the Navy's surface fleet and generate export orders.