Sir Keir Starmer left Washington on Friday night without any announcement on allowing Ukraine to fire long-range missiles into Russia.
The Prime Minister held intensive talks with President Biden in the White House to discuss pleas from Volodymyr Zelensky to let the country use the Storm Shadow missiles.
But John Kirby, a spokesman for the US national security council, said there would be no announcement on long-range missiles after the meeting, although he did not rule out one at a later date.
Foreign Office sources had briefed against expecting the green light at the end of Starmer’s visit, but it will come as a disappointment to leave empty-handed.