Ministers were tonight accused of failing to back Britain's steel industry after figures showed tens of millions of pounds of foreign metal was bought for major Government projects.
Whitehall departments spent £23million on imported steel, according to research by the GMB union.
It analysed official statistics for 2018/19 on where ministries purchased products for use in major projects.
The union said at least £7million was spent buying steel from abroad to use in school building schemes.
Nearly £4m was spent with foreign producers on steel for railway projects.
And the Ministry of Defence spent £6.8m on foreign metal, including for the Royal Navy's Dreadnought nuclear-armed submarines.
The Mirror revealed in 2016 how the four boats due to carry the Trident missile defence system would be partly-built with French steel.
The revelations come amid mounting fears for the future of the UK steel industry, which employs 32,000 people.