New Delhi, June 14 -- British Prime Minister Keir Starmer vowed Friday that he will fight to stay in office after the sudden resignation of his trusted defense minister left his shaky leadership weakened still further.

Starmer has seen the departure of several junior and senior ministers in recent weeks, as Labour Party lawmakers revolt and rivals plot, in despair at the government's relentless unpopularity.

But the sudden resignation of Defense Secretary John Healey is a heavy blow. Healey quit Thursday, warning that the government is not spending enough on the military to keep Britain safe "at this time of rising threats."

His departure hits Starmer in the one place the often embattled prime minister has won consistent praise: the wo...