Shadow business secretary Angela Eagle has criticised the previous Conservative-led coalition government for scrapping Labour's defence industrial strategy.
She said the strategy had made British jobs and industries the first priority in MoD contracts.
She told MPs: "We now have the deeply regrettable situation of an aircraft carrier, British surface ships and armoured vehicles all being manufactured in the UK with mainly imported steel, when, with more planning, our domestic industry could have supplied these needs."
The Commons debate, which is scheduled to last up to three hours, has been given an emergency slot amid growing fears for the industry.
Surely David Cameron and George Osborne could not be redder than Tony Blair and Gordon Brown?
The government has indicated it would consider taking a minority stake in the UK steel business as a "last resort".