A formal investigation into the political use of private data has been opened by the Information Commissioner.
Elizabeth Denham announced there would be a review into the use of data analytics for political ends amid concerns over allegations involving an analytics firm linked to a Brexit campaign.
In March, pro-Remain Labour MP Stephen Kinnock called on the Electoral Commission to investigate allegations that Leave.EU had not declared the role of the firm, Cambridge Analytica (CA), in its campaign.
The Information Commissioner's Office (ICO) then announced it was assessing how data analytics was being used.
Announcing the plans, Ms Denham said: "Having considered the evidence we have already gathered I have decided to open a formal investigation into the use of data analytics for political purposes.
"This will involve deepening our current activity to explore practices deployed during the UK's EU referendum campaign but potentially also in other campaigns."