The chairman of a powerful Commons committee has been reported to police by political blogger Paul Staines, who runs the Guido Fawkes website.
Mr Staines wrote in a letter to Scotland Yard: "The public interest is, you will no doubt agree, best served by holding elected law-makers to the highest standards.
"I urge you to proceed with an investigation using the evidence available".
Mr Yeo, who chairs the Energy and Climate Change Committee denies the claims and has referred himself to the Parliamentary Standards Commissioner.
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The slump will spark scrutiny, especially as statistics show a rise in racially or religiously motivated offences following the EU vote.
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Jordi Sanchez of the Catalan National Assembly and Jordi Cuixart of the Omnium Cultural group were jailed on Monday.