Since then, only seven Russian applicants have been rejected, while golden visas have been handed out to 202 Russian elites, each with at least £2m of investments in UK companies.

More than 250 of their family members and dependents were also given visas and can now live in the UK.

Labour MP Chris Bryant, who chairs a parliamentary group on Russia, called on the government to review “each and every” visa issued under the scheme.

“If they think corrupt elites are threatening our national security they cannot just sweep this under the carpet,” he told openDemocracy.

“Exploitation” of the golden visa scheme has led the UK to become a “particularly favourable destination for Russian oligarchs and their money,” according to a landmark report on Russia by the Intelligence and Security Committee in 2020.

“The UK welcomed Russian money, and few questions – if any – were asked about the provenance of this considerable wealth,” it said.

A Chatham House report into kleptocracy also described the golden visas as a “national embarrassment”, adding that “serious flaws and loopholes” remained in the system after the 2015 reforms.

It warned: “The UK has a long road ahead to address the risks from its servicing of post-Soviet elites and the suspicious capital that flows into the country in its billions.”

Russian nationals are the second largest group to have benefited from the golden visa scheme, with about 900 Russian applicants and 1,700 of their dependents being successful. The largest group is Chinese nationals and their families, of whom 4,247 successfully applied for golden visas.

The scheme allows them to circumvent a punishing and tortuous immigration process, as they are seen as “high value” individuals.

In a statement last week, the government said the scheme had been “under constant review” because “some cases had given rise to security concerns, including people acquiring their wealth illegitimately and being associated with wider corruption”.

But more than 200 golden visas were issued last year alone – including 22 to Russian millionaires.

“We are still in the dark about the true extent of abuse of the golden visa scheme,” said Rachel Davies, head of advocacy at Transparency International. “Individuals and their families from high-corruption risk countries were welcomed with open arms and no checks on the source of their wealth, but only a handful of names have ever been made public.”

She added: “Media investigations have shown how some of the visa recipients funded their lavish lifestyles with the proceeds of corruption.”

A review of visas issued under the scheme is due to be published “in the near future”, but opposition MPs have criticised the government for not acting sooner.

Labour’s shadow home secretary, Yvette Cooper, said: “For years the Conservatives failed to stamp out the influence of Russian money in the UK” adding that it had “taken international condemnation of our failures… for the home secretary to act”.

A government spokesperson told openDemocracy: “We keep all visas under review and should any individual be found to have breached their conditions, then we will take action.”