Britain last night demanded “cancerous growth” Vladimir Putin’s forces are pushed out of all Ukrainian territory - including Crimea, which they invaded eight years ago.
Foreign Secretary Liz Truss made the clearest statement yet of the UK’s intentions - as she warned the war may last a decade.
It comes after ministers stood by support for Ukraine to hit Russian targets on Russian soil.
Ms Truss said in a speech at Mansion House, in the City of London: “We are doubling down. We will keep going further and faster to push Russia out of the whole of Ukraine.”
Defence Secretary Ben Wallace backed the statement today, saying: “The international community believes Russia should leave Ukraine.
“The international community has condemned Russia for its invasion of Crimea, which was illegal in 2014.
"We've constantly said that Russia should leave Ukraine sovereign territory so that hasn't changed".
Mr Wallace said Vladimir Putin had failed to mount a swift victory in Ukraine so may become a “limpet” on a rock, wanting to “fortify and dig in” like in 2014.
The President could “just be a sort of cancerous growth within the country of Ukraine and make it very hard for people to move them out of those fortified positions,” Mr Wallace told Sky News.
He added: “I think it's really about if we want this to not happen, we have to help Ukrainians effectively get the limpet off the rock and keep the momentum pushing them back".
It comes after an escalation of tensions between the UK and Russia over Britain’s support for Ukraine using UK-delivered weapons.
Defence minister James Heappey said it is “entirely legitimate” for Kyiv’s forces to strike Russian targets on Vladimir Putin’s side of the border.
Mr Wallace backed that, saying today: "If Ukraine did choose to target logistics infrastructure for the Russian army, that would be legitimate under international law.
“They currently don't have British weapons that could do that, so it is unlikely that it is our weapons. We don't really have many long range weapons that are delivered in the way their army does."
Mr Wallace clarified that the long-range Brimstone missiles the UK is sending to Ukraine "will be used over the ground", but added that Britain is examining an anti-ship missile solution too.
The Defence Secretary told Sky News: "We have said we will source and supply, if we can, anti-ship missiles.
"It's incredibly important that the grain that affects us all, the food prices, does get to get out of Ukraine, that the Russians can't control the Black Sea".
He said Russian ships must not be allowed to be "used to bombard cities".
To date the UK has provided Ukraine with more than 5,000 anti tank missiles, five air defence systems with more than 100 missiles, 1,360 anti-structural munitions, and 4.5 tonnes of plastic explosives.
Britain has also sent over 90,000 ration packs, 10 pallets of medical equipment, 3,000 pieces of body armour, 77,000 helmets and 3,000 pairs of boots.
