Britain is planning a major military exercise to test how it could mobilise its large population of military veterans in preparation for a potential war.

The exercise would involve retired soldiers being called back into service, with officials describing it as a scale of mobilisation not seen in Britain for many years.

The plan comes as the UK faces growing concerns about threats from Russia and the possibility of a major conflict in Europe.

The exercise is intended to determine how quickly veterans could be contacted, organised, and brought into useful military roles if the country needed to expand its armed forces, The Telegraph has reported.

The government says the preparations are part of broader efforts to ensure Britain is ready for a serious national-security crisis and potential future conflict.