Video report by ITV News Correspondent Peter Smith
In the weeks since the Salisbury nerve agent attack, tensions between Russia and the West have mushroomed.
But what is it like to be caught in the middle of the two?
On Sunday, Defence Secretary Gavin Williamson will travel to the Baltic state of Estonia to visit British troops stationed there.
The UK-led NATO mission is stationed in the tiny European country, with a permanent force of around a thousand troops.
The former Soviet state shares some 180 miles of border with Russia.
Unlike Russia, Estonia is part of the EU and in Nato, but the city of Narva which lies eye-to-eye with Russia, with just a river separating the two, is in many ways resolutely Russian.
Many of Narva's 57,000 inhabitants speak Russian, eat Russian foods, and many still vote in Russian elections.
One woman told ITV News that the inhabitants of Estonia's third largest city were queuing up to vote in Sunday's Russian presidential election, with many backing Vladimir Putin.
Loyalty is rewarded and President Putin has a policy of protecting Russians, wherever they live in the world. This was his justification for sending troops into Georgia in 2008 and into Ukraine in 2014.
These military campaigns sent a chill through Estonia, the country's Foreign Minister recalled.
"It's [Russia's] expansionist ambitions have not changed since the collapse of the Soviet Union," Sven Mikser told ITV News.
"Recently they've been making much bolder moves when it comes to both conventional military build up as well as as attempts to politically divide us," he added.
Moscow has conducted numerous military exercises on its side of the border, with one in 2017 reportedly involving 100,000 troops.
Thousands of Estonians have responded to this perceived Russian aggression by joining the Estonian Defence League, a civilian army which trains for resisting invasion.
Business owner Õie-Mari Aasmäe is a recent recruit: "I decided that I needed to learn how to fight, so I joined the defence league."
She said she joined because "you never know what could happen, if for some reason something like this happens with us like it happens with Georgia and Ukraine, then we need to prepare for it."
However, unlike Georgia and Ukraine, Estonia has the shield of Nato membership, meaning that if President Putin were to send Russian troops over the river, it would not be just an attack on Estonia, but it would be interpreted as an attack on every Nato member, including the UK, and it is this deterant that Estonia relies on to shut President Putin out of the Baltics.