The UK backs the use of Storm Shadow missiles by Ukraine in Russia but will not publicly call for the move amid concern it would provoke a row with the US.
Volodymyr Zelensky has repeatedly asked to use the weapons, which can avoid enemy radar and hit precise targets up to 190 miles away, to strike deep inside Russia.
Despite confusion over the Government’s position, The Telegraph understands that Downing Street supports this.
However, the missiles are generally used alongside classified US systems, which requires the permission of Washington.
The Telegraph understands that the UK has not made a formal request to the US for Ukraine to use the missiles inside Russia. It is understood that US concerns about the move have been made clear.
A White House source told The Telegraph the Biden administration has concerns that their use, even without US approval, could escalate matters and lead to American troops being drawn into the conflict.
Sir Keir Starmer is understood not to want to provoke a row over the issue and is said to be taking a “consultative approach” to negotiations with the US on the issue after previous diplomatic rows under the Tories.
A Whitehall source said “We want to have discussions with allies on these sorts of things rather than wanting to push on and do it.”