More than 600 British companies set up in the last year are actually being controlled from Russia, openDemocracy can reveal.

It raises fresh concerns that unaccountable British company structures are being used to prop up oligarchs linked to Vladimir Putin.

The news comes amid calls to restrict the flow of Russian money through the UK and bring sanctions against allies of the Russian president.

Since January 2021, at least 623 firms have been set up by Russia nationals based in Russia, according to analysis by openDemocracy and Companies House expert, Graham Barrow.

They include a “web portals” company that was incorporated earlier today, which is majority owned by a Russian citizen who also lives in Russia.

Yesterday, a real estate business was set up by two Russian men who used a service address in London – but were in fact resident in Russia.

The analysis – which includes many legitimate companies – suggests that thousands of firms listed on the UK’s business register are controlled by Russian nationals who live in the country, with some linked to Putin’s allies.

Two British firms are controlled by Roman Abramovich, the owner of Chelsea football club, who lists Russia as his country of residence on official documents.

Russia’s richest man, Alexei Mordashov, also controls several British companies including his mining company, Nord Gold PLC.

Mordashov, who is thought to have the ear of Putin, supported the president last year by claiming that he “reflects pretty much what every average Russian has in mind”.

Another Russian billionaire who was named in Parliament this week as a “key enabler” for Putin has “significant control” over a British real estate firm that reportedly owns a four-storey townhouse in Mayfair.

Alisher Usmanov is a former shareholder of Arsenal football club and has a fortune of £8.9bn. He has faced calls for sanctions to be brought against him.

The company data seen by openDemocracy includes legitimate firms with no links to the Kremlin. But experts warned that the figures do not include limited partnerships, which have been commonly used in Russian money laundering.

Labour MP Chris Bryant today called on the government to seize the assets of Roman Abramovich – including his £152m home.

Bryant told MPs he had obtained a leaked Home Office document from 2019, which said Abramovich “remains of interest” to the UK government “due to his links to the Russian state”. It went on to suggest that some wealthy Russians should be “unable to base themselves in the UK”.

But Bryant said that “little” had been done to challenge the Chelsea owner since then.

Leader of the house Mark Spencer said the government had taken “very strong action against high-profile Russian individuals who are of concern”.

The UK has been a magnet for Russian oligarchs who have bought up property and business interests for years, with critics calling for stricter rules for companies and property owners.

A landmark report by the Intelligence and Security Committee in 2020 said that London had become a “particularly favourable destination for Russian oligarchs and their money”.

It added: “The links of the Russian elite to the UK – especially where this involves business and investment – provide access to UK companies and political figures, and thereby a means for broad Russian influence in the UK.”

At least 150 properties in the UK, worth £1.5bn, are owned by Russian businesspeople and officials who have been accused of corruption or having links to the Kremlin, according to Transparency International.

Today, Boris Johnson announced a range of sanctions against Russia in response to Putin's invasion of Ukraine – including freezing the assets of all major Russian banks.

There is no suggestion that any of the companies and individuals identified by openDemocracy have broken the law, or are necessarily linked to pro-Putin individuals.