The government is being urged to draw up legislation to force lawyers, lobbyists, politicians and others who do work for foreign governments such as Russia to register their activities.
Conservative MP Bob Seely told Sky News he is campaigning for the new law to end what he described as an “unhealthy, creeping influence” from hostile foreign powers.
The security services are understood to be keen on a UK version of the Foreign Agents Registration Act (FARA) in the United States. It requires individuals that work for foreign states to disclose that relationship and provide information about it.
A cross-government review is under way in the UK to identify any gaps in the current system that need filling, a Whitehall source said.
Mr Seely, a member of the parliamentary foreign affairs committee, thinks the gap is clear and requires new legislation to fix.
“Our system is too open to manipulation from those in and around the political system,” he said in a statement.
“It’s now clear that we need a Foreign Agents Act, which lists those people and organisations, PR types, bankers, lawyers and reputation peddlers, etc, who act for foreign states or their proxies in influencing government and public policy.”
The MP, a former soldier and an expert on Russian unconventional warfare, said he wants all MPs and members of the House of Lords to be banned from doing any paid lobbying for foreign governments.
“Our democracy needs to be open and transparent. There is an unhealthy, creeping influence in our political system. We need to treat this now,” he said.
Bill Browder, a Kremlin critic who describes himself as President Vladimir Putin’s number one enemy, said he agreed with Mr Seely’s call.
“It is a huge gap in the legislation which needs to be fixed urgently,” the American-born British financier said in an interview.
“In a globalised world and with London as one of the central nodes, foreigners are much more active here than they ever have been before, therefore you need some type of legislation to control that.”
Asked what the danger was if the government did not act, Mr Browder said: “Then you have dictators and kleptocrats effectively corrupting our system.”
Mr Browder is due to give evidence on Wednesday to the foreign affairs committee.
He said he planned to raise the impact of foreign influence on UK decision-making on Russia.
Mr Browder said he is concerned that the UK has yet to sanction any Russian individual suspected of gross human rights violations under a “Magnitsky amendment” to new sanctions legislation that was passed last year.
“I would argue that the reason no individuals have been sanctioned is because of the pollution of the political process by foreign influence,” Mr Browder said.
The amendment was named after Sergei Magnitsky, a Russian lawyer – employed by Mr Browder – who was arrested in 2008 after alleging that Russian officials were involved in large-scale tax fraud.
He died in a Moscow prison in 2009 after complaining of mistreatment.