A Metropolitan Police officer who told women he was a police officer so they would trust him has been convicted of rape and other serious sexual offences.
PC Dion Arnold, 33, was found guilty at Guildford Crown Court on Thursday 16 April of four counts of rape, two counts of assault by penetration, and two counts of sexual assault. He had faced 17 charges across four women; the jury acquitted him on nine counts. The offences spanned June 2023 to March 2025.
Arnold was attached to the South West Basic Command Unit, the Metropolitan Police’s operational policing unit for south-west London. It covers Wandsworth, Richmond upon Thames, Merton and Kingston upon Thames.
He met his four victims through online dating apps and, in at least one case, through his work as an Army reserves medic. He told them from the outset that he was a serving police officer. Chief Superintendent Dan Knowles, head of policing for the SW BCU, said Arnold did so “so that they would have more trust in him.”
Arnold also worked in a domestic abuse unit. That role gave him detailed professional knowledge of consent law.
The four women did not know each other. Investigators found a list of their names on Arnold’s phone. His own messages recorded him acknowledging that he had “gone too far” and apologising to the women. Despite this, his offending continued. Investigators found he repeatedly ignored them when they told him no.
Senior Crown Prosecutor Claire Gallagher, of the CPS South East Rape and Serious Sexual Offences unit, said Arnold “deliberately targeted women that he thought would not stop him and would never have the courage to report him. They have proved him wrong.”
The third officer from the same unit since 2023
Arnold is the third officer attached to the SW BCU to face serious sexual offence proceedings in three years.
In 2024, PC Cliff Mitchell, also attached to the unit, was convicted and sentenced to life in prison for multiple rapes. In March 2025, PC Nick Whitcombe, another officer from the same unit, was charged with rape. That case is ongoing.
Three officers from the same command unit charged with serious sexual offences in three years is not a random cluster. It is a documented pattern that raises questions about culture, vetting and professional standards within the BCU.
Chief Superintendent Knowles said the Met had “grown our professional standards teams over the last three years to ensure we are robust in investigating matters at the earliest opportunity.” He added that the force did not “underestimate the impact that cases like this have on the confidence that women and girls have in our organisation.”
The Met says it has overhauled its vetting and professional standards since 2022. Operation Onyx reviewed 1,636 completed sexual and domestic abuse cases and resulted in 378 individuals leaving the force. Around 1,500 officers and staff in total have exited since 2022. Knowles said internal reports of wrongdoing had “almost trebled” in three years.
Arnold joined the Metropolitan Police as a Special Constable in 2014 and became a regular officer in 2016. He was arrested by Surrey Police on 30 March 2025 after one woman reported offences against her between June 2024 and March 2025. He was suspended from duty shortly afterwards. Investigators then identified three further victims, with offending going back to June 2023. He had been offending for nearly two years before anyone reported him.
A misconduct hearing will follow the criminal proceedings. Under police regulations, a conviction does not automatically end an officer’s employment. The force must conduct its own formal process before Arnold can be dismissed.
He is due to be sentenced at Guildford Crown Court on Monday 22 June.
Support and reporting
Anyone who has experienced something similar can report to police by calling 101 (non-emergency) or 999 in an emergency. Anonymous reports can be made to Crimestoppers on 0800 555 111. Support is available from Rape Crisis England and Wales at rapecrisis.org.uk or on 0808 500 2222.
