Mohan Dash Singh, R (on the application of) v Director General of the Independent Office for Police Conduct

On judicial review of an IOPC review decision, the court must assess whether the IOPC lawfully concluded that the complaints investigation produced a reasonable and proportionate outcome. The court does not substitute its own view, decide the underlying police complaint, or require investigation of complaints which were not made. The review involves “double rationality”: whether the police investigation reached a fair and reasonable conclusion, and whether the IOPC’s conclusion that it did so was itself fair and reasonable. A failure to investigate a potentially relevant matter may properly be recorded as individual learning rather than unacceptable service where that conclusion falls within the range reasonably open to the investigator. The claim was dismissed because neither the investigating officer’s conclusion nor the IOPC’s review decision was legally irrational.

The claimant sought judicial review of an IOPC determination upholding the outcome of a local police complaints investigation. The complaints concerned the destruction or unavailability of CCTV and the alleged failure to interview an M&S assistant store manager in relation to an allegation of perverting the course of justice.

Permission was limited to a challenge to the conclusion that the failure to interview the assistant store manager in relation to a racially or religiously aggravated public-order offence was a learning point, but did not constitute poor service. The central issue was whether the IOPC’s conclusion that the complaints outcome was reasonable and proportionate was irrational or otherwise unlawful.

1. The claim was dismissed. The court’s role was confined to deciding whether the IOPC’s review decision was lawful and legally rational. It was not to decide whether the court would have reached the same conclusion as the police investigator or the IOPC, or to determine the underlying merits of the claimant’s original complaint.

2. The applicable approach was summarised in R (Ramsden) v Independent Police Complaints Commission [2013] EWHC 3969 (Admin) and confirmed as applicable to the IOPC statutory scheme in R (Watson) v IOPC [2020] EWHC 2859 (Admin). The police investigation must reach a fair and reasonable conclusion following a proportionate investigation. The IOPC’s task is to review whether that outcome was reasonable and proportionate. Judicial review involves an element of double rationality: whether the police conclusion was fairly and reasonably open to the investigator, and whether the IOPC was itself reasonable in upholding it.

3. The investigator was entitled to distinguish between the complaint actually made—concerning alleged perverting of the course of justice—and the separate question whether the assistant store manager should have been interviewed about the alleged racially aggravated public-order offence. The statutory scheme did not require an investigator to pursue every possible complaint emerging during an investigation.

4. In the particular circumstances, the investigator could reasonably treat the failure to consider interviewing the assistant store manager, or to document the reason for not doing so, as individual learning rather than unacceptable service. The investigator had the assistant store manager’s written account, other staff accounts and CCTV, and could reasonably conclude that an interview was unlikely to produce materially different evidence.

5. The IOPC reviewer was entitled to conclude that individual learning was a reasonable and proportionate outcome. Although another investigator or reviewer might have taken a more critical view, the decision was not so unreasonable as to amount to legal irrationality or otherwise to be infected by material public-law error. The claimant’s late attempt to add a new ground concerning the investigation of the racial-abuse complaint was refused.