This article is more than 2 years old

This article is more than 2 years old

Investigators from Britain’s data watchdog have spent nearly seven hours searching the London offices of Cambridge Analytica.

Eighteen enforcement officers entered the Cambridge Analytica headquarters in London’s West End on Friday night to search the premises after the Information Commissioner’s Office (ICO) was granted a warrant to examine its records.

The officials concluded the search at about 3am on Saturday.

“We will now need to assess and consider the evidence before deciding the next steps and coming to any conclusions,” an ICO spokesperson said in a statement.

A judge had issued the warrant on Friday evening, four days after the information commissioner, Elizabeth Denham, first announced plans to raid the offices.

Denham has been seeking access to records held by the London-based data analytics company, which faces allegations it may have illegally acquired the information of millions of Facebook users and used it to profile and target voters during political campaigns.

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Mr Justice Leonard granted the warrant after a five-hour hearing at the Royal Courts of Justice, adjourned from Wednesday.

A spokesperson for the ICO said: “This is just one part of a larger investigation into the use of personal data and analytics for political purposes.”

The focus of the data watchdog’s investigation includes the acquisition and use of Facebook data by Cambridge Analytica, its parent company, SCL, and Dr Aleksandr Kogan, the academic who developed the app used to gather the data.

Facebook Twitter Pinterest An ICO enforcement officer in Cambridge Analytica’s offices on Friday night. Photograph: Yui Mok/PA

The growing scandal stems from claims over the harvesting of personal data and whether it was used to affect the outcome of Donald Trump’s US presidential campaign and the EU referendum.

Less than an hour after the warrant was granted a group of 18 people, some wearing ICO enforcement jackets, entered the building from New Oxford Street, led by a woman holding a piece of paper that appeared to be a warrant.

The enforcement officers were seen on the second floor – where Cambridge Analytica is thought to have its offices.

It is understood they were searching for correspondence and communications between SCL and Kogan’s company Global Science Research (GSR), as well as data obtained from Facebook via Kogan.

News of the raid came as the acting CEO of Cambridge Analytica, Dr Alexander Tayler, who was appointed after the suspension of Alexander Nix, issued an apology about the way some data had been collected by an affiliate company.

Q&A How did the Cambridge Analytica story unfold? Show Hide Saturday 17 March The Observer publishes online its first story on the Facebook and Cambridge Analytica scandal, written by Carole Cadwalladr and Emma Graham-Harrison. Former Cambridge Analytica employee Christopher Wylie reveals how the firm used personal information taken in early 2014 to build a system that could profile individual US voters. The data was collected through an app, built by academic Aleksandr Kogan, separately from his work at Cambridge University, through his company Global Science Research (GSR). Sunday 18 March As the Observer publishes its full interview with Wylie in the print edition, the fallout begins. US congressional investigators call for Cambridge Analytica boss Alexander Nix to testify again before their committee. Monday 19 March Channel 4 News airs the findings of an undercover investigation where Cambridge Analytica executives ​boast of using honey traps, fake news campaigns and operations with ex-spies to swing election campaigns. Tuesday 20 March ​A former Facebook employee claims​ hundreds of millions of Facebook users may have had their private information harvested by companies in similar methods. Wednesday 21 March UK MPs summon Mark Zuckerberg to appear before a select committee investigating fake news, and accuse Facebook of misleading them at a previous hearing. Thursday 22 March It emerges Facebook had previously provided Kogan with an anonymised, aggregate dataset of 57bn Facebook friendships. Zuckerberg breaks his silence to call the misuse of data a 'breach of trust'. Friday 23 March Brittany Kaiser, formerly Cambridge Analytica’s business development director, reveals the blueprint for how CA claimed to have won the White House for Donald Trump by using Google, Snapchat, Twitter, Facebook and YouTube.

Photograph: Antonio Olmos

“I am sorry that, in 2014, SCL Elections [an affiliate of Cambridge Analytica] licensed Facebook data from a research company [GSR] that had not received consent from respondents,” he said. “The company believed the data had been obtained in line with Facebook’s terms of service and data protection laws.

“We are now undertaking an independent, third-party audit to verify that we do not hold any GSR data.”

Tayler went on to deny that a former employee who provided documents and information about Cambridge Analytica to the Observer was a whistleblower.

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He said: “The source of allegations against the company is not a whistleblower or a founder of the company. Christopher Wylie was a part-time contractor who left in July 2014 and has no direct knowledge of our work or practices since that date.

“He was at the company for less than a year, after which he was made the subject of restraining undertakings to prevent his misuse of the company’s intellectual property while attempting to set up his own rival firm.”

Meanwhile, pressure is mounting on the Facebook founder Mark Zuckerberg, who has been called to give evidence to MPs.

Play Video 3:41 What is the Cambridge Analytica scandal? - video explainer

Cambridge Analytica, SCL, Kogan and Facebook deny any wrongdoing.

Earlier in the week, the culture secretary, Matt Hancock, hinted that the government would consider further strengthening the information commissioner’s powers to investigate the misuse of personal data amid criticism that it had taken so long to get a search warrant.

Following Friday’s hearing, Leonard said he would outline the reasons for his decision on Tuesday.