However, in a recent interview with Sky News, Cabinet Office minister Pat McFadden said the UK is not considering introducing conscription to prepare for a potential war.
"But of course we have announced a major increase in defence expenditure," he said.
Prime Minister Sir Keir Starmer has committed to increase defence spending to 2.5% of GDP, but has not specified when.
Ministers said a defense review which will be published this spring will provide a "roadmap" for it.