Russia’s invasion of Ukraine "opened a new chapter" in post-Cold War history, said Boris Johnson as he agreed defence pacts with Sweden and Finland.

The prime minister visited Stockholm and Helsinki to sign the agreements, which say the UK will come to the aid of Sweden and Finland if they are attacked, and vice-versa if the UK is attacked.

Speaking in Helsinki, Mr Johnson said that aid given to Ukraine and support pledged to Sweden and Finland were key to countering Russian president Vladimir Putin, otherwise "this would not be the end of his neo-imperialist revanchist ambitions".

Ukraine news live: Russia demands apology after diplomat doused in ‘red paint’

Pressed on the rationale of supporting Ukraine while people in Britain are squeezed by the cost of living crisis, the PM pledged that "of course, there will be more support in the months ahead".

But Mr Johnson added: "It would be a huge, huge mistake to think that the economic answer is to let Putin get away with his barbaric behaviour in Ukraine."

The prime minister made the remarks at a news conference alongside Finland’s president Sauli Niinisto.

It comes as both Sweden and Finland consider joining NATO amid Russia’s ongoing military aggression in Ukraine.

That could be seen as provocative by the Kremlin, but Mr Niinisto placed the blame firmly with the Russians for becoming more aggressive in their insistence on the countries’ neutrality – and because they had shown they were "ready to attack a neighbouring country".

"My response would be that you caused this – look at the mirror."

Mr Johnson said it was a "pivotal moment" in the UK and Finland’s shared history.

He added: "The Russian invasion of Ukraine has changed the equation of European security and it has rewritten our reality and reshaped our future.

"We’ve seen the end of the post-Cold War period and the invasion of Ukraine sadly has opened a new chapter.

"Finland has traditionally been neutral but this [agreement] is formalising and making clear something that needs to be made explicit in the context of today.

"That is that, in the event of an attack on either of us, we will come to each other’s support."

© Sky News 2022