Officials say that before Russia’s full scale invasion of Ukraine, all Nato allies combined were only able to produce tens of thousands of 155mm artillery shells a year.

The 32 members are now able to manufacture two million rounds a year. That is a dramatic increase, but still short of Russian production levels – an estimated three million artillery shells a year.

The MOD’s war-gaming this week will focus on the supply chains for artillery munitions and uncrewed systems – also known as drones.

They are the very same stocks being expended in their thousands every week in Ukraine.

An MOD official said the war-gaming would play out “real-time, war-time scenarios” and place realistic stresses on supply chains.

The purpose of the exercise is to understand vulnerabilities in the supply chain and to inform future investment decisions.

Defence companies taking part in the exercise include BAE Systems, MBDA, Lockheed Martin and Babcock.

The government’s defence industrial strategy is due to be published in the spring. It will form part of a wider defence review currently underway.

The government has promised to increase defence spending. It says it will set out a path to reaching a target of spending 2.5% of GDP on defence next year.