Information Commissioner Elizabeth Denham (pictured) said: "The behavioural advertising ecosystem has been applied across to political campaigning to influence how we vote. I am deeply concerned that this has happened without due legal or ethical consideration of the impacts to our democratic system."

Speaking at a European Parliament hearing on the Facebook and Cambridge Analytica case, she said: "Online platforms can no longer say that they are merely a platform for content; they must take responsibility for the provenance of the information that is provided to users."

The ICO’s investigation on the issue of data for political purposes began in May 2017, before reports emerged on the alleged misuse of data by Cambridge Analytica. The regulator is focusing on specific allegations and enforcement as well as producing a report on the wider implications of the findings.

Denham said the issues raised by the scandal would lead to reform in the online political advertising industry. "Our investigation and action in this case will change the behaviour and compliance of all of the actors in the political campaigning space."

However, the report’s recommendations go beyond the remit of the ICO, and are likely to be relevant for other regulators "overseeing electoral process and academic research", she added. The ICO plans to publish the report by the end of the month.