The office building that used to be occupied by the now defunct Cambridge Analytica | Chris J Ratcliffe/Getty Images Cambridge Analytica did work for Brexit groups, says ex-staffer The disgraced data analytics firm did work for the Leave side of the 2016 Brexit vote, according to emails.

LONDON — Cambridge Analytica, the disgraced data analytics firm, conducted work for the Leave.EU campaign and the United Kingdom Independence Party ahead of the 2016 referendum on European Union membership, according to a former Cambridge Analytica official.

The revelation — outlined in internal emails between the data analytics firm and the political groups and submitted on Tuesday to the British parliament — contrasts with repeated denials by both Leave.EU and UKIP that they used Cambridge Analytica to target voters during the Brexit ballot.

Brittany Kaiser, the former head of business development at the firm, said that Leave.EU used datasets created by Cambridge Analytica to target voters with online political messages to potentially sway public opinion in 2016. The company has been at the center of a worldwide scandal about the illegal scraping of digital information from millions of Facebook users without their consent, and how this data was potentially then used for targeted political advertising.

"I have strong reasons to believe that those datasets and analyzed data processed by Cambridge Analytica as part of a Phase 1 payable work engagement ... were later used by the Leave.EU campaign without Cambridge Analytica’s further assistance," Kaiser wrote to Damian Collins, the head of the U.K. parliament's digital, culture, media and sport committee, which has held a series of hearings into the matter over the past 18 months.

"The fact remains that chargeable work was done by Cambridge Analytica, at the direction of Leave.EU and UKIP executives, despite a contract never being signed," she added, alongside a number of internal documents outlining the relationship between her former employer and the British political groups.

“When we said we’d hired Cambridge Analytica, maybe a better choice of words could have been deployed" — Arron Banks, co-founder of Leave.EU, in June 2018

This potential targeting of U.K. voters on social media ahead of the Brexit vote is part of a wider push by political groups across the Western world and beyond to use digital political campaigning to target people with increasingly sophisticated messages. It comes as lawmakers and policymakers are calling for greater oversight over how these groups use the likes of Facebook, Twitter and Google amid concerns that there is a lack of control over how these digital political campaigns operate.

"Data profiling of voters was done at a more sophisticated level in the referendum than ever before," Collins, the British politician, told POLITICO. "It's a big concern, we should pass emergency legislation to mandate transparency in political campaigns."

Leave.EU and UKIP have repeatedly denied they paid Cambridge Analytica for work ahead of the Brexit referendum despite public statements from Arron Banks, the co-founder of Leave.EU, that his group had hired the firm. Later, he backtracked to say that no contract had ever been signed between the two sides.

“When we said we’d hired Cambridge Analytica, maybe a better choice of words could have been deployed,” Banks told U.K. lawmakers. “Did we hire them? Clearly not, because we didn’t pay them or sign a contract.”

Representatives for both UKIP and Leave.EU were not immediately available for comment.

Cambridge Analytica went bankrupt after its role in online targeting of voters, particularly in the United States, became public in 2018. Facebook has also been fined $5 billion by U.S. authorities and smaller amounts by British and Italian ones for its role in the data scandal over accusations that it did not sufficiently protect its users' data from widespread data collection by political groups. The social networking giant is appealing.

In a series of internal emails provided by Kaiser, the former Cambridge Analytica executive, to the U.K. parliament on Tuesday, the relationship between Cambridge Analytica and the Brexit groups is outlined in greater detail than ever before. That included discussions between both sides on early-stage voter analysis conducted by the firm, as well as concerns about whether such work could have broken the U.K.'s data protection rules.

According to the documents, Cambridge Analytica executives discussed strategy with Leave.EU over how to publicize the firm's findings, and planned at least one dinner with Nigel Farage, the frontman for the Leave.EU campaign.

In previous U.K. parliamentary testimony, Kaiser said that the firm had sent a £41,500 invoice for its work on the Brexit referendum to UKIP, in part so that it could analyze the political party's internal data because Leave.EU did not hold much digital information on its own.

"We are working with the campaign and their various partners to identify, profile and engage voters in the lead-up to the referendum on Britain’s EU membership," according to an internal Cambridge Analytica email that outlined its relationship with the Brexit groups. "We have extensive experience providing data-driven political communications advice to campaigns around the world, including at the highest level of U.S. politics."