He said: “First and foremost I think is the sense of foreboding that Ukraine is struggling and that the tide may be turning in favour of Russia.

“Despite grievous losses over the past two years of conflict, it appears that the Russians have been able to make up their losses in men and equipment far quicker than expected and establish superiority in numbers on the battlefield.

“Recent estimates from the UK’s respected think-tank the Royal United Services Institute (RUSI) suggest that Russia has twice as many troops on the front line as Ukraine – 510,000 to 250,000 – and is poised to revive its offensive.

“This two-to-one advantage gives Russia the luxury of being able to concentrate forces where it hopes to make advances, like it has in the Kharkiv area recently.

Lt. Col. Stuart Crawford added: “Ukraine, on the other hand, has to try to defend all along the 1,200 kilometre front line or prioritise its defence plans and be prepared to cede more of its territory.

“Ukraine’s troops are, in effect, all in the ‘shop window’; General Kyrylo Budanov, head of Ukraine‘s military intelligence, has stated: ‘I’ve used everything we have… unfortunately, we don’t have anyone else in the reserves.'”

The US only passed the military aid bill for Ukraine in April after months of deadlock in Washington.

Republican Party hardliners in the Senate blocked the bill for months, with some opposing more American cash being spent abroad, while others wanted concessions on other issues such as immigration.

The $95billion package (which also included aid for Taiwan and Israel) was eventually approved in the House, pathing the way for weapons to be sent to Ukraine.

But Lt. Col. Crawford fears the aid may now arrive in Ukraine too late.

He said: “The sad truth is that Ukraine has been starved of support by dead-eyed, sharp-suited politicians in Washington who seem happy to petty-politick on American domestic issues while soldiers die in frontline trenches in the Donbas. They have blood on their hands and we should not let them forget it.

“US military aid, plus more from other nations including the UK, will probably arrive just in time to prevent Ukrainian forces from being overwhelmed. But it didn’t have to be on a knife edge like this, and casualties have mounted as the west dithered.”