Boris Johnson promises 'massive package' of sanctions against Russia following Ukraine invasion

Addressing the nation following the incursions overnight, Mr Johnson vowed that Britain “cannot and will not just look away” and said that measures in response would be designed to “hobble the Russian economy”.

In the message, broadcast at noon, Mr Johnson said: “A vast invasion is under way by land, by sea and by air. And this is not, in the infamous phrase, some faraway country of which we know little.

“We have Ukrainian friends in this country, neighbours, co-workers. Ukraine is a country that for decades has enjoyed freedom and democracy, and the right to choose its own destiny.

“We and the world cannot allow that freedom just to be snuffed out. We cannot and will not just look away.”

“It’s because we’ve been so alarmed in recent months at Russian intimidation that the UK became one of the first countries in Europe to send defensive weaponry to help the Ukrainians,” he added.

“Other allies have now done the same and we will do what more we can in the days ahead.

“Today, in concert with our allies we will agree a massive package of economic sanctions designed in time to hobble the Russian economy. And to that end, we must also collectively cease the dependence on Russian oil and gas that for too long has given Putin his grip on Western politics.

“Our mission is clear. Diplomatically, politically, economically, and eventually, militarily, this hideous and barbaric venture of Vladimir Putin must end in failure.”

Dozens of fatalities have been reported across Ukraine since explosions were first heard in the capital Kyiv in the early hours of this morning.

Mr Putin announced the action during a televised address early on Thursday morning, saying the move was a response to threats from Ukraine.

He said Russia does not have a goal to occupy Ukraine, but the responsibility for bloodshed lies with the Ukrainian “regime”.

Russia’s military said it has targeted Ukrainian air bases and other military assets and has not targeted populated areas.

Mr Putin issued a stark warning to other countries that any attempt to interfere with the Russian action would lead to “consequences they have never seen”.