The United Kingdom is set to unveil its long-delayed Defence Investment Plan on Tuesday, setting out how it intends to modernise its ageing military. Britain plans to make major investments in drones, artificial intelligence, autonomous systems and traditional deterrents such as fighter jets, submarines and nuclear weapons.Outgoing Prime Minister Keir Starmer is expected to publish the blueprint after months of delay and a funding dispute that led to the resignation of John Healey as defence secretary. The plan is expected to include £5 billion in funding for drones over the next four years, marking Britain’s biggest investment so far in uncrewed military technology.“The character of warfare is rapidly changing,” Dan Jarvis, Healey’s successor as defence secretary, said ahead of the announcement. He said conflicts in Ukraine and West Asia had shown how uncrewed systems were increasingly shaping modern warfare.The investment plan comes at a time when Britain is trying to rebuild its depleted armed forces and prepare for the possibility of a major war by 2030. The Labour government has promised to raise defence spending to 2.6% of GDP next year and 3.5% by 2035, but it has not yet set out a clear path for how spending will rise between those two points.The blueprint is also expected to detail funding for large defence programmes such as the Global Combat Air Programme fighter jet, the AUKUS submarine project and Britain’s nuclear deterrent. However, tight budget limits mean some projects may be cancelled, delayed or slowed.According to Bloomberg, plans for a Type 83 destroyer are no longer expected to go ahead. The purchase of 12 US-made F-35A jets, which are capable of carrying tactical nuclear weapons, may be pushed back. Programmes to recruit new cadets and refurbish military accommodation may also be slowed.The Ministry of Defence is facing a funding gap of about £28 billion over the next four years. The Treasury has agreed to provide around £15 billion in additional funding, but it remains unclear how far this will go in meeting the armed forces’ requirements.The plan has already drawn criticism from opposition parties. The Conservative Party called it “too little, too late”, while Liberal Democrat leader Ed Davey accused the government of short-changing the armed forces.What is the Defence Investment Plan?The Defence Investment Plan is the UK government’s 10-year defence investment and procurement blueprint. It is meant to translate the recommendations of the 2025 Strategic Defence Review into funded programmes, procurement decisions and industrial priorities.The Strategic Defence Review, published on June 2, 2025, described Britain as facing “a new era of threat” because of Russia’s war in Ukraine, China’s military expansion, rapid advances in autonomous technologies and growing cooperation among Russia, China, Iran and North Korea.The review found that the British armed forces were not fully prepared for modern, high-intensity warfare. It highlighted gaps in munitions stockpiles, procurement speed, industrial capacity, recruitment, retention, drone technology, artificial intelligence, cyber warfare and integration across land, sea, air, cyber and space domains.Among its major recommendations were an expansion of the Royal Navy’s nuclear-powered attack submarine fleet, investment in Britain’s sovereign nuclear warhead programme, a hybrid navy combining crewed and uncrewed vessels, new munitions factories and a more lethal army built around AI, drones, long-range fires and digital networks.The Defence Investment Plan is the first major step towards implementing that vision.Why drones are at the centre of the planThe UK is seeking to learn from the Russia-Ukraine war, where drones have become central to battlefield surveillance, targeting, electronic warfare and precision strikes.Under the new plan, drones are expected to operate alongside helicopters and jets. The army could acquire up to 24 armed drones by 2030 to fly alongside its Apache helicopter fleet. These drones are expected to carry out reconnaissance, precision strikes and electronic warfare missions.The Royal Navy is also expected to move towards a “hybrid navy” made up of crewed and uncrewed vessels. Instead of replacing ageing warships with a new destroyer model, the UK is expected to procure at least six common combat vessels from the early 2030s. These would be supported by armed uncrewed vessels, missile platforms and underwater systems designed to detect and destroy enemy submarines, naval threats and aerial threats.However, several details remain unclear, including how many uncrewed naval systems will be acquired and when they will enter service.What it meansThe Defence Investment Plan marks a shift in Britain’s military thinking. Instead of relying only on a smaller number of expensive crewed platforms, the UK is trying to build a more distributed force that combines drones, AI, autonomous systems, submarines, fighter jets and nuclear deterrence.But the central challenge remains money. The plan promises a major technological upgrade, but Britain’s armed forces still face a large funding gap. The success of the blueprint will depend on whether the government can match its ambitions with sustained spending, faster procurement and enough industrial capacity to deliver equipment on time.