A Royal Navy ship monitors a Russian frigate in the North Sea. Three new warships have been commissioned.Photograph: MoD Crown Copyright/PA

The Royal Navy is facing questions over whether three new warships will be built with British steel as its Scottish supplier faces deepening financial difficulties.

Liberty Steel Dalzell, a plate mill in Motherwell, has struggled to pay its bills and workers in recent weeks, according to several people with knowledge of operations.

The government said it was "closely monitoring" the situation at the plant, amid growing concerns over its survival.