Sir Keir Starmer has vowed to make the UK “battle-ready” as he launched the long-anticipated Strategic Defence Review (SDR), revealing the Government’s plans to counter looming threats from hostile states including Russia and China.

In a move not seen in a generation, the British Army is now set to grow — with numbers rising to at least 76,000 full-time soldiers in the next Parliament. The announcement marks a reversal in decades of downsizing, as ministers attempt to plug gaps in the armed forces. At present, the army stands at just 70,800 regular troops, below the current target of 73,000.

Veterans may also be called upon to take part in annual training exercises, ensuring former service personnel are ready to fight if needed.

The Prime Minister declared he was “100 per cent confident” the defence overhaul would be delivered. However, the ambitious plans hinge on increasing defence spending to 3 per cent of GDP by 2034 — a target that has sparked warnings from top Labour figures and economists alike over the rising cost to taxpayers.

Next week’s spending review is also expected to see winter fuel payments reinstated, while the controversial two-child benefit cap looks set to be scrapped — further fuelling concerns over how the spending spree will be funded.

Paul Johnson, director of the respected Institute for Fiscal Studies, issued a stark warning on the airwaves, telling Times Radio: “There would have to be some really quite chunky tax increases” to afford both the defence and welfare pledges.

Former Foreign Secretary Jack Straw echoed the view, saying: “Taxes will have to rise. I don’t see any alternative to that and at the same time, there will have to be some quite difficult retrenchment, particularly on parts of the social security budget.”

While Justice Secretary in 2009 under the Labour governement of Gordon Brown, Straw was at loggerheads with many in his party when he refused to ban wealthy tax exiles from making party political donations.

The Express reached out to Mr Straw's office for further comment.

The 140-page document, unveiled on Monday, pulls no punches in outlining the UK’s current vulnerabilities. It highlights serious shortcomings across the armed forces — from insufficient weapons stockpiles and overstretched medical services, to a personnel crisis which leaves only a fraction of troops combat-ready.

“The UK is entering a new era of threat and challenge. The West’s long-held military advantage is being eroded as other countries modernise and expand their armed forces at speed, while the United States’ security priorities are changing”, the report warns.

It adds that Britain must be prepared to “absorb and respond to surprises and shocks” — yet concedes that defence reforms are lagging behind the speed and scale of new dangers.

The document paints a sobering picture of the decades ahead, which it says will be shaped by “multiple and concurrent dilemmas, proliferating and disruptive technologies, and the erosion of international agreements that have previously helped to prevent conflict between nuclear powers”.

There is also unease among reviewers about the potential creation of genetically targeted pathogens, with fears that artificial intelligence and facial recognition could be weaponised by drones to identify and strike individuals based on ethnicity or other traits.

One insider issued a chilling warning about the misuse of emerging technologies, saying: “The genie is already out of the bottle.”