India, July 1 -- Self-flying fighter jets, uncrewed submarines and drones will be at the center of Britain's future military under a defence plan being announced on Tuesday that reflects a world of conflicts transformed by technology.

The Defense Investment Plan has been repeatedly delayed as military leaders and Treasury officials wrangled over the cost of equipping the UK military for an increasingly dangerous world.

Like other NATO countries, the UK is under pressure to increase defence spending to counter a more aggressive Russia and less reliable United States. John Healey resigned as defence secretary on June 11, accusing the Government of being unwilling to spend enough on the military at a time of "rising threats."

Healey argue...