Russian forces suffered an average of around 1,500 dead and injured per day in Ukraine during October, according to the UK’s chief of defence staff.

Admiral Sir Tony Radakin told the BBC that the Russian people were paying an “extraordinary price” for Russian President Vladimir Putin’s invasion, saying that October was the worst month for losses since the conflict began in February 2022.

“Russia is about to suffer 700,000 people killed or wounded – the enormous pain and suffering that the Russian nation is having to bear because of Putin’s ambition,” he told the Sunday With Laura Kuenssberg programme.

He said that while Russia was making gains and putting pressure on Ukraine, the losses were “for tiny increments of land”.

The cost of the war, which he put at more than 40% of public expenditure on defence and security, is also “an enormous drain” on Russia.

With the election of US president-elect Donald Trump casting doubt on US support for Ukraine, Sir Tony said Western allies would stand with them for “as long as it takes”.

“That’s the message President Putin has to absorb and the reassurance for President Zelensky,” he said.

Writing in The Sunday Times, Sir Tony said the growing threat from authoritarian states, including Russia, North Korea, and the Iranian-backed Houthi movement in Yemen, is putting the international community “under immense strain”.

“This is a new era of competition and contest that will last for decades and has the potential to be more disruptive to our economy and our security than anything Britain has experienced in modern times,” he wrote.