Rupert Lowe MP v ICGS: High Court rules parliamentary privilege bars judicial review of MP disciplinary proceedings

The High Court has held that a challenge by Rupert Lowe MP to an Independent Complaints and Grievance Scheme investigation into his conduct is barred by parliamentary privilege and therefore not justiciable. Mr Justice Chamberlain delivered judgement on 14 May 2026 in R (Rupert Lowe MP) v Independent Complaints and Grievance Scheme [2026] EWHC 1163 (Admin), following a preliminary issue hearing on 17 March 2026.

Background

The ICGS received a complaint against Mr Lowe on 28 January 2025, with further allegations added in April 2025. On 23 July 2025, the scheme notified Mr Lowe that one allegation had passed initial assessment and would proceed to full investigation. Mr Lowe, who had by then left Reform UK and founded the Restore Britain party, contended that the complaint was politically motivated and made in bad faith.

He brought judicial review proceedings on three grounds: that the decision to investigate was irrational; that the complaint was vexatious and made as part of a campaign of harassment; and that the ICGS had exhibited apparent bias in his favour. The defendant, the Speaker of the House of Commons (the ICGS having no separate legal personality), raised parliamentary privilege as a threshold objection to the entire claim.

The privilege framework

The Speaker did not rely on Article 9 of the Bill of Rights, which protects freedom of speech and debates in Parliament from impeachment or question in any court. The submission rested instead on the common law principle of exclusive cognisance: that the House of Commons retains sole jurisdiction over its own internal affairs, and that courts should not interfere.

Chamberlain J surveyed the relevant authorities, including Bradlaugh v Gossett (1884), R v Parliamentary Commissioner for Standards ex p Al Fayed [1998], and R v Chaytor [2010] UKSC 52. The critical question arising from Chaytor was whether the Resolution of 23 June 2020, by which the House accepted Dame Laura Cox's recommendation for an independent disciplinary process, had waived or relinquished the House's exclusive cognisance over this category of complaints.

Five reasons for exclusive cognisance

The court identified five features of the ICGS's function that pointed to the continuation of parliamentary privilege notwithstanding the structural reforms.

First, investigating complaints of bullying and harassment against MPs is a disciplinary function directed at the propriety of MPs' conduct. Discipline has historically been recognised, in both Bradlaugh and Al Fayed, as falling within the exclusive cognisance of the House.

Second, the House has constructed a comprehensive internal framework, comprising the ICGS, the Parliamentary Commissioner for Standards and the Independent Expert Panel, chaired by a former senior judge. The existence of that framework suggests complaints were intended to be resolved within it.

Third, the potential sanctions available, including suspension and expulsion, directly affect an MP's capacity to perform their parliamentary functions and require confirmation by the House. Even a lesser sanction, or the fact of an investigation itself, may affect an MP's reputation and standing.

Fourth, coherence requires that the whole process attract privilege. It would be incoherent to permit judicial interference at the investigative stage when any court would accept it could not interfere with a subsequent recommendation to the House to impose serious sanctions. Quashing or staying an ICGS investigation would, in effect, prevent the House from exercising its disciplinary function.

Fifth, complaints may be politically motivated, as Mr Lowe himself alleged. There are sound constitutional reasons for reserving such determinations to Parliament's carefully calibrated internal framework rather than to the courts.

Significance

The judgement clarifies that the Resolution of 23 June 2020 effected a delegation of the House's exclusive cognisance, not a waiver of it. The reforms that removed the Standards Committee's supervisory role and created the IEP did not bring ICGS decisions within the supervisory jurisdiction of the courts. MPs facing ICGS investigations have no avenue to challenge the decision to investigate by way of judicial review. Challenges to procedural or substantive decisions within the disciplinary framework must be pursued through the IEP appeal process.

The claim was dismissed as not justiciable. Written submissions were invited on the terms of the order.