Boris Johnson is set to fly to Sweden and then Finland on Wednesday for security talks after Vladimir Putin’s invasion of Ukraine.
The two countries are considering joining Nato following the Russian president’s attack on Ukraine.
Becoming part of the military alliance would be a major geo-political shift for the Nordic nations.
Finland could announce a bid for membership within days, according to local reports, while Sweden is currently conducting a review of whether it should join.
Finland shares a border with Russia, and the Kremlin has repeatedly warned of “serious consequences” if the two countries join the military alliance, including potentially stationing nuclear weapons in its Baltic enclave of Kaliningrad.
Speaking ahead of Mr Johnson trip, the Prime Minister’s official spokesman said: “It’s about not just Ukraine but broader security of Europe.
“This is about meeting other democratic countries and discussing issues such as security which is of importance both here and overseas.
“We support a country’s democratic capabilities to decide on things like Nato membership.”
Just days ago, Defence Secretary Ben Wallace said it was “inconceivable” that the UK would not support Finland or Sweden if either were attacked, regardless of whether they were members of Nato or not.
He made the comment as he spoke at a press conference in Niinisalo, Finland.
Responding to questions from the media, he said: “It’s inconceivable that Britain would not come to the support of Finland or Sweden if it was ever attacked.
“[That’s] Without any big formal agreement. We are European countries who share the same values, who have deep, long histories, a significant number of the British population seem to be descended from Vikings anyhow.
“We have that cultural link. I cannot conceive of a time where we would not come to support Finland and Sweden, no matter where they were with the Nato debate and where they are with agreements.”
