Allegations of unlawful campaigning in the 2016 EU referendum

On 4 March 2017, the Information Commissioner's Office (ICO) reported that it was 'conducting a wide assessment of the data-protection risks arising from the use of data analytics, including for political purposes' in relation to the Brexit campaign.

[1][2] In May 2017, the ICO also launched an investigation into the use of data analytics for political purposes, making reference to both the EU referendum and the 2015 general election.

[3][4][5] In March 2018 The Economist published an article stating that breaches of electoral law were unlikely to have had a substantive effect on the outcome of the EU Referendum: "Does any of this matter beyond Westminster?

[11][12] The Information Commissioner's Office has found Leave.EU guilty of breaking the Privacy and Electronic Communications (EC Directive) Regulations 2003 and the Data Protection Act 1998 on a number of counts.

[22] In February 2017, the Electoral Commission announced that it was investigating the spending of Britain Stronger in Europe and Vote Leave, and smaller organisations, as they had not submitted all the necessary invoices, receipts, or details to back up their accounts.

[31] Press speculation continued, both on the question of the ultimate source(s) of the Constitutional Research Council's donation, and the legitimacy of its use, which included £282,000 for pro-Brexit advertising in the Metro newspaper, which does not circulate in Northern Ireland.

[38] In March 2017, the Electoral Commission cleared Vote Leave of breaking spending limits, but in October 2017 it re-opened the investigation due to new evidence.

[40] Having not declared £675,000 incurred under a common plan with Darren Grimes´ Brexit campaign BeLeave, Vote Leave unlawfully overspent its £7m limit by £449,079.

[41][42] In September 2018, the High Court of Justice found that Vote Leave had received incorrect advice from the UK Electoral Commission, but confirmed that the overspending had been illegal.

[45] Vote Leave attempted to prosecute the Electoral Commission for publishing its July 2018 report 'Report of an investigation in respect of: Vote Leave Limited, Mr Darren Grimes, BeLeave, Veterans for Britain', alleging that it had caused 'reputational damage', but their request for judicial review was rejected in January 2019, since the Electoral Commission's publication had been lawful.

[47][51] On 19 June 2019, a cross-party group of 38 of the 73 UK Members of the European Parliament wrote to the Venice Commission, a body of the Council of Europe charged with assisting Council members regarding constitutional law, to request an investigation into "the breach of spending rules and data-protection laws" and "the exclusion of non-UK EU citizens residing in the UK from the franchise".

[52] In 2018, the intelligence and security committee of the UK Parliament, under the chairmanship of Dominic Grieve, began researching a report on allegations of Russian interference in the 2016 Brexit referendum.

[54] In February 2019, the Digital, Culture, Media and Sport select committee's 18-month investigation into disinformation and fake news published its final report,[55] calling for an inquiry to establish, in relation to the referendum, “what actually happened with regard to foreign influence, disinformation, funding, voter manipulation, and the sharing of data, so that appropriate changes to the law can be made and lessons can be learnt for future elections and referenda”.

On 13 September 2019, the Metropolitan Police concluded that while "it is clear that whilst some technical breaches of electoral law were committed by Leave.EU in respect of the spending return submitted for their campaign, there is insufficient evidence to justify any further criminal investigation",[65][66] and on 24 September 2019, the National Crime Agency said it had found no evidence of criminality in respect of the issues raised by the Electoral Commission and that no further action would be taken.

Ball brought a crowdfunded case against the MP and Vote Leave chairman Boris Johnson, alleging misconduct in public office on the grounds that he knowingly lied when claiming that the UK sent £350m to the EU each week and that this could instead be spent on the National Health Service.