A British public inquiry has concluded that Russian President Vladimir Putin likely ordered the attempted assassination with the nerve agent "Novichok" against Russian double agent Sergei Skripal seven years ago, Reuters reports.
Since the turn of the century, Britain's relations with Russia have been steadily deteriorating amid accusations from both sides of espionage and abuse, exacerbated by the 2022 invasion of Ukraine.
Here's a timeline of some of the key events in the relationship over the past 25 years.
2000 - In March, British Prime Minister Tony Blair became the first Western leader to visit Vladimir Putin, before he had even won the Russian presidential election. The following month, Putin traveled to London to meet Blair and Queen Elizabeth.
2003 - Putin went to Britain in June for a four-day state visit - the first Russian leader to do so since 1874 - to rebuild diplomatic bridges after relations were tarnished by the Iraq War. The Queen hosts a state lunch for him at Buckingham Palace.
2006 - In January, Russia accuses Britain of carrying out a spy operation involving the use of a receiver hidden in a fake rock to collect classified information from agents.
2006 - Alexander Litvinenko, a former Russian intelligence agent who defected to Britain in 2000 and a long-time critic of Putin, dies in November after drinking green tea laced with the radioactive isotope polonium-210 in London. Before his death, he accuses Putin of being responsible.
2007 - British prosecutors charge former Russian spy Andrei Lugovoi with poisoning Litvinenko, further damaging diplomatic relations already strained by his death. Russia denies any involvement and refuses to extradite him. In the ensuing dispute, both countries expel four of their diplomats.
2010 - In December, Britain and Russia retaliate by expelling diplomats accused of involvement in espionage.
2011 - British Prime Minister David Cameron visits Russia and meets with Putin in September in an attempt to thaw relations and improve trade.
2012 - Cameron joins Putin to watch judo at the London Olympics - the first trip by a Russian leader to London since 2006.
2013 - In July, the British government rejects holding a large-scale public inquiry into Litvinenko's death, saying that relations with Russia played a role in the rejection, but denying that this was the main consideration.
2014 - A year after its rejection, Britain says, that it will conduct an investigation, but denies that it is related to tensions over Russia's annexation of Crimea and Moscow's support for Syrian President Bashar al-Assad.
2016 - The investigation concludes that Lugovoi and another Russian, Dmitry Kovtun, carried out the murder of Litvinenko as part of an operation likely led by Russia's Federal Security Service (FSB) and approved by Putin.
2018 - In March, former Russian double agent Sergei Skripal and his daughter Yulia were found slumped on a bench in Salisbury, southern England.
The UK claims they were poisoned with the nerve agent Novichok and that Moscow is likely responsible. It expels 23 Russian diplomats it claims are spies, charges the Kremlin denies.
Four months later, Briton Dawn Sturgess dies after being exposed to the nerve agent. Police later charge three Russians it says were GRU military intelligence officers in absentia with the attempted murder of Skripal.
2022 - Britain becomes one of the most vocal supporters of Ukraine after Russia's invasion in February, with military support and sanctions against Russian individuals and entities.
2024 - Britain says it will expel Russia's defense attaché, strip some properties of diplomatic status, and limit the duration of Russian diplomatic visas over "malign activity" Moscow.
Russia responded by expelling Britain's defence attaché, and in September the Russian security service FSB revoked the accreditation of six British diplomats accused of espionage and sabotage.
In October, the head of Britain's domestic intelligence agency MI5 said that Russia's GRU military intelligence agency was determined to wreak havoc across Britain and Europe, and the following month Moscow expelled another British diplomat for espionage just months after his arrival.
2025 - In March, a group of Bulgarians were convicted in London of participating in a Russian spy ring. Days later, Russia expelled two more British diplomats accused of espionage.
In October, a group of Britons were convicted of arson at a Ukrainian business in London, which prosecutors said was at the behest of the Russian mercenary group "Wagner".