British troops have been told by Boris Johnson that their deployment on Nato’s flank with Russia was “fundamental” for the security of the alliance’s members.

The Prime Minister greeted and joked with British armed forces stationed in Estonia during his trip on Tuesday to eastern Europe.

Mr Johnson told UK servicemen and women the world enjoyed “greater peace and security because you are on the front line of our collective Western defence”.

He also wished troops from the Royal Welsh regiment a happy St David’s Day when he met them at the Tapa base.

In impromptu remarks about the importance of their role, he told them: “I think what you’re doing is fundamental for the safety, security of all of our nations, but also of our values – freedom, democracy, independent sovereign nations.

“That’s what we believe in, that’s what Nato sticks up for.”

The Prime Minister met the serving personnel alongside Nato secretary-general Jens Stoltenberg and Estonian Prime Minister Kaja Kallas.

He joked that Ms Kallas had told him British troops were “behaving particularly well”, to which Ms Kallas told Mr Johnson they should “keep it that way”.

When Mr Johnson asked the gathered troops who liked Tapa, he was met with muted cheers. When he asked who liked Tallinn, there was no audible reply.

The Prime Minister was shown around by Lieutenant Colonel Simon Worth, Commanding Officer of the Royal Tank Regiment Battlegroup.

Speaking to personnel, Mr Johnson said it was “pretty nippy” in Estonia and discussed being allowed to drive one of the armoured military vehicles on a previous visit.

“When I first came here you let me drive one at some point,” he said. “Straight over the tundra.”

Following the visit to Tapa, Ms Kallas said Nato needed to find “more ways to cripple Putin’s war machine”.

She tweeted: “This is a clear signal of unity, strong support and solidarity.

“Our unwavering message in this current crisis: we must stop Putin’s war and #StandWithUkraine.”

Mr Johnson replied via social media, tweeting: “You have our full support Kaja.

“We are committed to helping Ukraine and protecting our Nato friends & allies – exactly why we’ve doubled numbers of British troops in Estonia in recent weeks.”

Separately, Mr Johnson held talks with Estonian president Alar Karis in which they discussed the Ukraine crisis and Nato’s response to the Russian invasion.

A No 10 spokeswoman said: “The leaders condemned Russia’s invasion of Ukraine and their brutal attacks on innocent civilians, which they agreed had the hallmarks of a dark past which the European continent thought was forgotten.

“The Prime Minister and President Karis agreed that the world must come together to denounce Russia’s action and support the people of Ukraine.”

Mr Karis thanked the British leader for choosing to double the UK’s troop presence in Estonia to “fortify Nato’s defences” at the alliance’s border with Russia.