Donald Trump's America waded into the row over funding for Britain's Armed Forces today with a senior official saying the world needed more UK 'military strength'.US under-secretary of war, Elbridge Colby heaped pressure on Sir Keir Starmer to act as the beleaguered Prime Minister reeled from the resignation of two of his defence ministers over a lack of cash for the Ministry of Defence.Sir Keir is under pressure to bring forward a major programme of spending amid fears that the Treasury is trying to provide as little as it can, possibly as little as £10billion, little more than a third of half what experts say is needed.Ahead of a by-election next week that is likely to trigger a leadership challenge from returning MP Andy Burnham, the PM today effectively begged Labour MPs for more time as he insisted defence is his 'number one priority'.But sharing the devastating resignation letter from outgoing defence secretary John Healey, Mr Colby highlighted 'the courage, tenacity, dedication, daring, and loyalty' of British servicemen and women in two world wars 'that won them the lasting admiration and gratitude of the whole world'.'The United Kingdom has an extraordinarily proud military history. It commands our respect,' Mr Colby wrote on X.'There is again a great need for more British military strength in this critical time. We urge the UK to meet that need with urgency, scale, and determination.'The Trump administration has long demanded its Nato allies increase their military spending, amid fears that it cannot be relied upon to defend Europe from any Russian attacks.As Sir Keir's grip on power loosens further:The PM faces the prospect of heading to a G7 summit alongside Donald Trump next week with the UK's defence plans in shambles;More evidence has emerged of a Russian military build-up on the border with Europe; Mr Carns, a former Royal Marine, has hinted he will stand in any Labour leadership contest;The premier still needs to find a replacement for Mr Carns and two ministerial aides, as well as a new security minister; Meg Hillier, a ringleader of a previous Labour revolt against welfare curbs, has said she believes MPs are now ready to support cuts; US under-secretary of war Elbridge Colby heaped pressure on Sir Keir Starmer to act as the beleaguered Prime Minister reeled from the resignation of two of his defence ministers