Ben Wallace is under pressure to rethink his failure to back Britain's shipbuilding industry in light of Russian aggression in Ukraine.
The GMB Union warned Mr Wallace the "threat of war is not abstract" - adding the UK's shipbuilding and ship repair sectors "are essential to our national security."
It comes after the MoD told the Defence Select Committee that it will "not provide a guaranteed pipeline of work for UK yards" when the refreshed Shipbuilding Strategy is published.
