In response to Vladimir Putin sending 'peacekeeping' troops into Ukrainian territory, the UK imposed sanctions upon three Russian billionaires and five banks.
The current sanctions are designed to hit Gennady Timchenko, Boris Rotenberg and his nephew Igor Rotenberg, who are said to be "very close to the Putin regime", according to Boris Johnson.
Further controversy arose when Labour MP Margaret Hodge questioned why Chelsea FC owner Roman Abramovich had not been sanctioned.
Boris Johnson "misspoke" when claiming in the House of Commons that Abramovich had already been sanctioned.
Labour MP Ben Bradshaw said: "The three oligarchs he’s sanctioned today have been sanctioned by the US for four years. We need to do better than that."
So who are the three oligarchs?
Who is Gennady Timchenko?
69-year-old Gennady Timchenko is reportedly worth £17.3 billion, according to Forbes.
His private investment group, Volga, specialises in energy investments, among other opportunities and his net worth makes him the 78th richest person in the world.
He has faced US sanctions since 2014 due to his reportedly close ties with Putin. He is also major shareholder in Rossiya, which supported the destabilisation of Ukraine after the annexation of Crimea in 2014, according to the government.
Rossiya is also one of the five banks sanctioned by the UK.
He reportedly once told a Russian news agency: "You have to pay for everything in your life. Even for your friendship with the president."
The government has imposed travel bans and frozen the assets of each billionaire listed in its first wave of sanctions.
Foreign Secretary Liz Truss said: "[This] will hit oligarchs and banks close to the Kremlin. It sends a clear message that the UK will use our economic heft to inflict pain on Russia and degrade their strategic interests."
Who is Boris Rotenberg?
Boris and Igor Rotenberg have both been sanctioned by the UK as the uncle and nephew respectively have reportedly got extremely close ties to Putin's regime.
Forbes estimates that Boris' net worth is around £880 million thanks to his association with SMP bank, co-owned with brother Arkady, Igor's father.
Both Arkady and Boris, 65, were also hit by the sanctions Bradshaw referred to in the Commons, imposed by the US in 2014.
The US treasury has claimed that Boris and Igor were awarded billions worth of contracts with Gazprom ahead of the Sochi Olympics in 2014.
Boris' association with Putin seems to be notably close, with the two knowing each other since childhood and regularly playing ice hockey together.
Who is Igor Rotenberg?
At 47, Igor is the eldest son of Arkady Rotenberg with a fortune believed to be around £809 million
It's thought that his wealth derives mainly from his role with his control of Gazprom Drilling, sold to him by Arkady.
The businessman, also chairman of the board at National Telematic Systems, told Reuters at the time: "Of course my father gave me a good start in business.
"Today I am an independent businessman and I am developing my assets with my team in a competitive, market environment."
Of the current sanctions, Foreign Secretary Liz Truss said further measures are ready if Russia invades any more of Ukrainian territory
Truss said that while these sanctions are ready to be imposed, the government would stop short of giving back any money given by Russian-linked donors to the Conservative Party.
She said: "All of the donations to the Conservative Party are from people on the electoral register in Britain, those donations are properly declared."
