Sir Keir Starmer ignored Vladimir Putin’s threats of nuclear war by insisting Ukraine must be given “what it needs” to defeat Russia.
The Prime Minister told the Kremlin the “quickest way to end this conflict” is to withdraw their troops from Europe’s biggest land war since 1945.
Western allies – including Britain – are under intense pressure to allow Ukraine to use long-range missiles to strike targets deep inside Russia.
Moscow marked 1,000 days since its invasion by updating its weapons doctrine so that any large conventional attack on the Russian capital could meet the criteria for a nuclear response.
But Sir Keir, speaking to reporters at the G20 Summit in Brazil, said: “Russia is the aggressor in Ukraine, and today is the day that marks 1,000 days of the conflict.
“That is 1,000 days of Russian aggression, 1,000 days of Ukraine suffering from that aggression, and we’ve said throughout that we stand firmly with Ukraine.
“We must ensure Ukraine has whatever is needed for as long as it’s needed.
“The quickest way to end this conflict is for Russia to cease, and that is the quickest, most simple and just way to do this.”
He added in a seperate interview: “This is a thousand days of conflict and there is a very high cost if Russian aggression is seen to pay off.
“A cost that we will all pay, because this is not just about sovereignty in Ukraine, it’s about our freedoms.
“It’s about our way of life and it impacts everybody across the United Kingdom. But, you know, we are working of course with allies to make sure Ukraine is in the best possible position.”
The changes to the nuclear doctrine came after Washington gave the green light for the use of US long-range missiles within Russia and amid speculation that the UK could follow suit with British-supplied Storm Shadow weapons.
Shortly after the updates were rubber-stamped, Moscow’s defence ministry said Ukraine had fired six US-made ATACMs missiles.
The ministry said it shot down five and damaged one more, in a statement carried by Russian news agencies.
Earlier on Tuesday, Ukraine’s general staff said the Ukrainian army had carried out a strike on the arsenal of the 1046th logistics support centre in the area of Karachev in the Bryansk region.
Former Defence Secretary Grant Shapps warned Sir Keir’s inability to make a decision will bolster dictators around the world and cost thousands of lives.
The Prime Minister’s has still not lifted restrictions on Storm Shadow missiles, which can hit targets 150 miles away.
Asked about Storm Shadow missiles, Sir Keir said on Tuesday morning: “My position has always been that Ukraine must have what it needs for as long as it needs. Putin must not win this war.
“But look, forgive me, I’m not going to go into operational matters, because there’s only one winner if I do that, and that is Putin and it would undermine Ukrainian efforts.
“I’m not going to do that. But here at the G20 and for many, many weeks, I’ve been making the case that Ukraine must have what it needs for as long as it needs that we must put Ukraine in the strongest possible position to win this war.
“It impacts Ukraine, but it impacts all of us, and Russia cannot be allowed to win this war.”
America allowed Kyiv to use Army Tactical Missile Systems, (ATACMS), after North Korean troops joined Moscow’s soldiers in the conflict.
Ukrainian forces could now use the ATACMS to strike Russian and North Korean troops, key pieces of military equipment, ammunition depots, supply lines deep inside Russia and logistics hubs.
Fears are intensifying that Vladimir Putin’s forces could launch a major assault, with an estimated 50,000 soldiers, on Ukrainian positions in Kursk.
The Kremlin is believed to want to retake all of the Russian territory seized by Kyiv in August.
Dmitry Medvedev, who has been serving as deputy chairman of the Security Council of Russia since 2020, said that in this case, this could amount to WW3.
He said: “The use of alliance missiles in this way can now be qualified as an attack by the bloc’s countries on Russia.
“In this case, the right arises to launch a retaliatory strike with weapons of mass destruction against Kiev and the main NATO facilities, wherever they are. And this is already WWIII.”