A former teacher has been jailed after taking covert photos of children in a leisure centre changing room as part of an incident which led to his persistent grooming and abuse of children being uncovered.

Former teacher, Mathew Gilkes, 47, has been jailed for 16 years plus an additional five-year licence at Preston Crown Court, having previously pleaded guilty to 42 offences including so-called ‘upskirting’ and child sex offences. An indefinite sexual harm prevention order was also imposed to prevent further offending.

Gilkes was arrested after his car was traced from the leisure centre where children reported seeing him with his phone held under their cubicle taking photographs while they were changing.

Over 80 electronic devices, including mobile phones, computers, cameras, memory cards and spy pens were recovered from his address which included over 5,000 indecent images and videos of children.

His devices also revealed he has been posing online as two different teenage boys, as well as a woman, in order to groom and manipulate young girls via social media.

Stacey Gosling for the Crown Prosecution Service said: “Mathew Gilkes is a sexual predator and a danger to children.

“Not only did he abuse his position by taking covert intimate images of children, but he also sought out other victims online and at the leisure centre for his own sexual gratification.

“He gave no thought to the lasting damage his abuse would have on young victims and, when caught by police, was found to have a staggering number of indecent images showing his depraved offending knew no limits.

“I would like to thank the victims for reporting the abuse and supporting the prosecution as without their intervention, Gilkes’ online grooming operation may well have continued in secret.

“I hope today’s outcome sends a clear message that the Crown Prosecution Service are dedicated to bringing those that exploit children to justice.”

Gilkes offending came to light when two children in the changing rooms of a leisure centre reported that they saw a mobile phone under the door as they were changing after swimming on 1 August 2024.

Two weeks later, a similar incident was reported with Gilkes caught on CCTV at the centre.

Police arrested Gilkes near his home address on 14 August 2024. He made no comment in his police interview and when his home was searched, over 80 electronic devices were found including mobile phones, computers, cameras, memory cards and spy pens.

Over 5,000 indecent images and videos were found on his devices, of which, over half were images or videos taken under clothing without consent, offences more commonly known as ‘upskirting’.

Officers also found two fake social media accounts, where he was posing as a teenage boy. Gilkes had spoken to a large number of girls under 16 where he engaged in sexualised communication, shared intimate images and encouraged them to engage in sexual activity despite being unable to consent as they were underage.

Conversations were also found on another platform where Gilkes was posing as a 29-year-old woman. He engaged in sexual communication with the profile of a girl who was just 14 years old.

His school issued laptop also contained indecent images and search terms indicating he was seeking out indecent images of children.

The children he offended against have been deeply affected by his deplorable actions with one victim saying it has impacted every part of her life and another saying she is frightened, insecure and has become distrusting.

Gilkes pleaded guilty to 42 charges on 12 November 2025, during a hearing at Preston Crown Court.