Prime minister Boris Johnson will today sign historic declarations with Sweden and Finland today to reinforce their security and fortify northern Europe’s defences, in the face of renewed threats.

As fellow liberal democracies, and members of the Joint Expeditionary Force, both nations are already vital security partners in Northern Europe, with world-leading defence capabilities and cutting-edge technology development.

Visiting Harpsund, the Swedish PM’s country residence, and Helsinki, the PM will set out the UK’s intention to support the two nations’ armed forces should either face crisis or come under attack.

This morning Boris Johnson signed mutual security assurances with PM Andersson in Sweden, and this afternoon he will travel to Finland to sign a similar security declaration with President Niinistö.

The declarations will see a step-change in defence and security cooperation between the UK and each country, intensifying intelligence sharing, accelerating joint military training, exercising and deployments, and bolstering security across all three countries and northern Europe.

They will also see the UK bolster its collaboration on traditional threats facing all three nations, while working also with Sweden and Finland to tackle new geopolitical challenges, such as hybrid and cyber threats.

Johnson will also make clear the UK’s unwavering support for NATO’s open door policy during the visit.

Boris Johnson said in light of the news: “We are steadfast and unequivocal in our support to both Sweden and Finland and the signing of these security declarations is a symbol of the everlasting assurance between our nations.

“These are not a short term stop gap, but a long term commitment to bolster military ties and global stability, and fortify Europe’s defences for generations to come.

The declarations signed today will allow the UK to cooperate with key Nordic partners and their armed forces, in all domains, including cyberspace. They will also allow for closer collaboration on new technology and intelligence gathering.

As part of increased defence cooperation with Sweden and Finland, the UK will offer to increase deployments to the region, including with Royal Air Force, British Army and Royal Navy assets and personnel.

Both Sweden and Finland have played a key role in supporting Ukraine to defend itself in recent weeks and months, while British, Swedish and Finnish forces have exercised together across the High North and the Baltics.

Both nations are part of the UK-led Joint Expeditionary Force taskforce, which brings together 10 countries in support of stability and security in the North Atlantic, Baltic Sea Region and the High North. The assurances made today build on the already close ties of that defence grouping.

Today’s visit comes after No 10 welcomed the Swedish and Finnish leaders to Downing Street in March to discuss closer security and defence ties.