The House of Commons petitions committee is investigating allegations of fraud in connection with a petition calling for a second EU referendum.
Its inquiry is focused on the possibility that some names could be fraudulent -77,000 signatures have already been removed.
More than 3.2 million signatures are on the petition, but PM David Cameron has said there will be no second vote.
The UK voted by 52% to 48% to leave the EU in Thursday's referendum.
Helen Jones, who chairs the cross-party petitions committee, said in a statement posted on Twitter that it was taking the allegations "very seriously".
Of course, the fact that massive fraud has been obvious for days (10,000 signatures from the Vatican) didn't stop the credulous muppets of the German public televisions news shows from reporting all those signatures with a condescending smirk, as if they were real.