Afghanistan, June 30 -- British Prime Minister Keir Starmer has announced the country's largest defence investment in decades, pledging to sharply increase military spending in response to what he described as a more dangerous and unstable global security environment.

Speaking on Tuesday, Starmer said the plan would raise defence spending from 2.3% to 2.7% of gross domestic product, with a long-term goal of reaching 3% and eventually 4.2%. The government will allocate an additional £15 billion, taking total defence spending over the next four years to nearly £300 billion.

Starmer said Britain faces growing security challenges, citing the war in Ukraine, instability in the Middle East, rising living costs and emerging cross-borde...