Probe launched into use of private data for political purposes
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."
Ms Denham said it was "understandable" that "political campaigns are exploring the potential of advanced data analysis tools to help win votes", but said the "public have the right to expect that this takes place in accordance with the law".
She added: "This is a complex and rapidly evolving area of activity and the level of awareness among the public about how data analytics works, and how their personal data is collected, shared and used through such tools, is low.
"What is clear is that these tools have a significant potential impact on individuals' privacy. It is important that there is greater and genuine transparency about the use of such techniques to ensure that people have control over their own data and the law is upheld."
Ms Denham said the investigation was a "high priority for her team" and that she was "conscious" that it coincides with the General Election campaign.
Commenting on the investigation, a Conservative Party spokesman said: "The Conservative Party fully complies with all the requirements of electoral and information law.
"Digital campaigning techniques help ensure that the public are informed, and will drive up democratic participation across society."
Leave.EU's head of communications Andy Wigmore said there was "nothing to investigate".
He told the Press Association the Information Commissioner was under "political pressure ... based on stories which are completely false and a total misunderstanding of what really goes on and a total misunderstanding of the short period, and a total misunderstanding of the Electoral Commission's rules".
He said Leave.EU "had nothing to hide and never had anything to hide ... Cambridge Analytica did zero work for us".
Mr Wigmore added: "This is just another example of political pressure from the Remainers to try and justify why they lost - they lost, get over it."
Ms Denham later told BBC Radio 4's The Media Show: "We have been in touch with Cambridge Analytica.
"We've been in touch with a company called Aggregate IQ, which is based in Canada.
"We've been in touch with political campaigns and other data analytics companies.
"What we're trying to do is shine the light on the use of personal data of voters to target them in some way during political campaigns.
"I think it's important the public understands how their data may be used."
Ms Denham added: "The important part of our investigation is there's been allegations, there's been a lot of trade and analysis of people's digital trails online that then allows political campaigns to serve up ads that are micro-targeted to individuals."
Ms Denham also said the investigation will examine how parties use data in the current election, with data protection guidance refreshed last week.