The writer is a former US naval officer and senior adviser at the Atlantic Council think-tank Is Britain a formidable military power today? Sadly, no. Even though the UK would only enter a conflict with partners, its conventional forces are now critically underpowered. Indeed, the total number of active duty personnel — about 150,000 — is smaller than the US Marine Corps.

Last month’s UK Defence Command Paper, which sets out a strategy for meeting current and future threats, does not help. It offers no viable vision or strategic plan to reverse this condition. The paper relies heavily on repeating concepts from the US National Defense Strategy rather than setting a course demanded by today’s realities. More radical thinking is needed.

Ben Wallace, Britain’s outgoing defence secretary, has promised the country will spend at least ￡100bn a year on its military by 2030; about double what it spends today. But given inflation, the purchasing power of this sum will have withered in seven years’ time.