The British Army is close to being "combat incapable against high-end threats", such as those posed by Russia and China, a senior defence analyst has said.
Francis Tusa has sounded a warning about the UK's "neglect" of its heavy equipment programme through recent decades.
The UK has made a commitment to generate a NATO high-readiness brigade by 2024.
However, Mr Tusa believes that is becoming less likely.
He told Forces News: "The problem is overwhelmingly with equipment.
"Will there be the equipment to equip a coherent, mechanised/armoured brigade by 2024, trained? And the answer is no."
New equipment on the horizon will not be ready in time.
The Challenger 3 main battle tank is not due to be fully operational until 2030. The British Army will get a 148-strong fleet of Challenger 3 tanks, which are expected to reach initial operating capability by 2027.
And there are widely publicised problems with the Ajax armoured vehicle, including vibrations that have caused sickness and hearing loss among personnel in trials.
As part of "modernising" plans, meanwhile, a planned upgrade to the Warrior has been cancelled, with the armoured vehicle being retired by the mid-2020s and the capability replaced by Boxer.
In a statement, a Ministry of Defence spokesperson said: "...[we] will spend over £85bn on equipment over the next four years and we are committed to delivering state-of-the-art equipment and world-class capabilities".