Theresa May questioned over 'shady' links between Brexit campaign and data mining firm at heart of Facebook scandal

Cambridge Analytica whistleblower claimed the UK could have voted to stay in EU without Vote Leave 'cheating' during Brexit referendum

Theresa May has faced questions over the "shady" link between Brexit campaign groups and the firm at the heart of the Facebook data row.

SNP Westminster leader Ian Blackford grilled the Prime Minister over allegations of "cheating" in the EU referendum, in the wake of sensational allegations from two whistleblowers, who claimed that Vote Leave had breached spending limits during the Brexit campaign.

Christopher Wylie, a former director of research at scandal-hit Cambridge Analytica, told MPs on Tuesday that Vote Leave and other pro-Brexit groups had found a common way to flout spending rules during the 2016 campaign.

Mr Blackford called for "all allegations of improper spending" to be fully investigated, as he pressed Ms May over the links between pro-Leave groups and Canadian firm Aggregate IQ (AIQ), which is connected to Cambridge Analytica.

Speaking during Prime Minister's Questions, he said: "We know that before the EU referendum, the DUP received £425,000 from the Conservative-run Constitutional Research Council (CRC), chaired by Richard Cook, former vice chair of Scottish Tories.

"We know that some of the money was given to Aggregate IQ, a reported franchise of Cambridge Analytica.

"We know that Chris Wylie is absolutely convinced of a common purpose between Vote Leave, BeLeave, Veterans for Britain and the DUP.

"The shady business of data mining and undermining electoral law goes right to the heart of the Prime Minister's party. Will the Prime Minister issue the full details of the transactions between the DUP and the Scottish-Tory linked CRC?"

However the Prime Minister dismissed the claims, saying there are strict laws in place to govern electoral spending.

Ms May said: "I understand this is a matter that has already been investigated twice by the Electoral Commission... If there are allegations of criminal activity that should be taken to the police."

The row comes after Mr Wylie sparked an international outcry with revelations that Cambridge Analytica harvested Facebook data from more than 50 million profiles, which he claimed was used to influence voters in foreign elections.

Mr Wylie and his former colleague Shahmir Sanni, both of whom worked for Vote Leave, have instructed lawyers to hand over a dossier of evidence to the Electoral Commission outlining their claims that it acted illegally during the referendum campaign.