"Their intervention will almost certainly fly in the face of EU state aid rules under EU law," the Conservatives said. "Corbyn’s broadband plan will almost certainly be illegal under EU law."

They added in a statement: "Corbyn’s Labour won’t be able to introduce their scheme unless they ditch their plan to extend Britain's membership of the EU and abandon their plans to hold a chaotic second referendum."

(Reporting by Guy Faulconbridge; editing by Stephen Addison)