"Mr Chandler is described as having been 'an object of interest to the DST [France's Directorate of Territorial Surveillance] since 2002 on suspicion of working for the Russian intelligence services," Seely told the Commons. "These documents are brief, terse, factual files listing activities, associations and judicial actions. They have been authenticated by senior French intelligence sources and by British and American counterparts familiar with their contents." Loading Seely said Chandler's file was marked "S" which he said meant he was regarded as a "high or higher level of threat to France". He said the letter S is used by the French to designate radical Islam and in Monaco, where the documents originated, S was used to denote counter-espionage cases. He urged Chandler to provide an explanation saying he could be an "innocent party".

"Now it may be that Mr Chandler can provide a satisfactory explanation or argue these relationships, if they existed, are historic or are somehow misrepresented in the documents and I do not use privilege lightly," he said. Seely supported the 'leave' campaign as did Chandler's think-thank. The Legatum Institute hit back at the allegations. "Christopher Chandler has never been associated directly or indirectly with Russian intelligence or the Russian state," a spokesman told Fairfax Media. "Neither Christopher Chandler nor anyone at Legatum is aware of any such alleged 'investigation' by French authorities, not 16 years ago or at any time since.

Loading Replay Replay video Play video Play video "To be clear Christopher Chandler has never been approached at any time by the French or any other authorities regarding Russia and maintains a sterling record of ethical business practices earned over many decades. "These accusations are complete nonsense, and have been previously rebutted by the Legatum Group." Loading

The institute's most high-profile political figure, trade expert Shanker Singham, who recently left for the Institute of Economic Affairs, privately advises Foreign Secretary Boris Johnson, Trade Secretary Liam Fox and the other prominent Leave campaigner Michael Gove. Chandler is the founder of Dubai-based investment company Legatum Group, which funds the London-based think-thank the Legatum Institute Foundation. He and his brother set up a company called Sovereign Global in Monaco in 1986. In the 90s, they began investing in Russia's state-owned gas giant Gazprom. In 2006, the brothers de-merged Sovereign and Christopher Chandler created the Dubai-based Legatum Group and, in 2009, founded the Legatum Institute in Mayfair, London. Last year, The Mail on Sunday, which takes a different stance on Brexit to its daily publication, The Daily Mail, first reported on Russian links to the pro-Brexit Legatum Institute. It did not allege the links to Russian intelligence asserted by Seely on Monday. The paper claimed the institute was attempting to drive a so-called 'hard Brexit'. The Institute dismissed the report as nonsense and "comical if it weren't so serious" and said Singham had been appointed six months prior to the Brexit referendum.