The Court of Appeal has held that it is unarguable that the Prime Minister’s decision to notify the EU of the UK’s intention to withdraw from the EU was unlawful on the basis that the 2016 referendum was invalidated by certain leave campaigners exceeding campaign spending limits: R (Wilson) v Prime Minister  EWCA Civ 304.
The Electoral Commission found in May, July and November 2018 that various leave campaigners (including Vote Leave and Leave.EU) had overspent contrary to the Political Parties, Elections and Referendums Act 2000 and that offences appeared to have been committed. Based on this, the applicants argued that the referendum was invalid and that the Prime Minister’s decision to notify the EU of withdrawal was unlawful as a result of being based on an invalid referendum, or alternatively that the Prime Minister acted irrationally in deciding not to revoke the withdrawal notification following the Electoral Commission’s findings.
Ouseley J refused permission to proceed with the judicial review on the basis of delay and lack of merit. The Court of Appeal affirmed this decision, finding that the claim was unarguable on the basis that the referendum was advisory and Parliament had retained ultimate control over whether the UK left the EU. The court therefore had no common law power to intervene. Even if the court did have a power to intervene in relation to the results of a non-binding referendum, a minimum requirement for the exercise of any common law power would be that a breach of voting rules was material such as to affect the referendum results. There was no evidence that the result of the referendum would have been different as a result of the overspending.
The Court of Appeal also held that the decision to notify was lawful. The notification took place on 29 March 2017 when the Prime Minister could not have been aware of the illegalities that took place in the campaign. Further, for a mistake of fact to give rise to a public law challenge the error must have played a material part in the reasoning of the decision. As stated above, there was no evidence that this was the case. Finally, the Prime Minister’s power to notify was derived from the EU (Notification of Withdrawal) Act 2017, not the referendum itself, meaning that the lawfulness of the notification did not depend upon the lawfulness of the referendum.
In its concluding remarks, the Court of Appeal emphasised that “courts are not concerned at all with the merits of leaving or remaining in the EU” and that “Judicial review is not, and should not be regarded as, politics by another means.”