Admiral Sir Tony Radakin, the head of the Armed Forces, said on Sunday that Russia’s invasion is not going well, that the country is more isolated and less powerful, and that it “cannot continue”.

Britain could raise its defence spending as soon as this month, as the Ministry of Defence plans to review its military upgrade based on the failings of Russian forces in Ukraine.

Dominic Raab, the Deputy Prime Minister, warned that the West would require “strategic stamina” in its response to Moscow. Even though sanctions have “put the squeeze on Putin”, the conflict is likely to drag on for “months, if not years”, the Justice Secretary warned.

Mr Johnson has called for further sanctions on Russia, as Mr Blinken confirmed that the US and its allies were having a “very active discussion” about banning the import of Russian oil and natural gas.

The price of oil leapt almost 20 per cent on Monday morning trading in Asia as Brent crude briefly touched $139 [£105] per barrel, before falling back. Oil has not been above $130 since 2008.
 

Britain will also pledge an extra $100 million to the Ukrainian government to help it pay public sector salaries, fund welfare and keep critical state functions operating.

Mr Johnson said that “while only Putin can fully end the suffering in Ukraine”, the funding “will continue to help those facing the deteriorating humanitarian situation”.