British Defense Secretary John Healey published his resignation letter at lunchtime on Thursday, quitting his post amid a dispute over military spending plans for the coming years.

The unexpected resignation compounds pressure on under-fire UK Prime Minister Keir Starmer, who in recent weeks had seemed to weather the worst of a storm about a potential challenge for the Labour Party leadership.

Britain's Defense and Finance ministries had been locked in talks for months on how quickly to increase defense spending in the next few years.

The clash pits strained public finances and anemic growth forecasts against NATO targets to continue increasing European defense expenditures.

The UK is making faster progress than many in NATO on defense spending, but shortfalls in the erstwhile global superpower's military capabilities — particularly at sea — had prompted considerable scrutiny and criticismImage: Simon Dawson/Avalon/Photoshot/picture alliance