A teacher who featured in the Channel 4 documentary series Educating Cardiff has pleaded guilty to sexually assaulting a 17-year-old girl.

Gareth Ritter, 44, of Bryngwyn, in Monmouthshire, was in the middle of giving evidence in his defence when his barrister asked for the charge to be put to him again.

Ritter, who was also a prominent member of a number of brass bands, was asked to stand up and, when asked how he pleaded, he said “guilty”.

He was told all of the charges he had admitted carried a custodial sentence and the court would consider immediate custody.

Ritter had previously denied intentionally touching the teenager sexually without consent when he was in his 30s.

Earlier in the trial, the jury was told that, following an event in Cardiff, Ritter offered to drive the victim home but stopped at a flat he owned in Cardiff Bay, saying he had to check it before a new tenant arrived and invited her in.

Once inside, she said he touched her bottom while they stood on a balcony overlooking the city and later kissed her in the hallway.

The woman, now in her 20s, said: “One hand went around my back, it dropped to my bum and he lent in and kissed me.

“I remember his tongue going into my mouth.

“I remember being against the wall, I couldn’t step back, I remember him kissing me. I turned my face away, my hands were on him, I wasn’t forceful, I held out my hands on his chest. It was a light push but not forceful.”

Asked by prosecutor Andrew Davies if she said anything to him, she replied: “It might seem like a strange comment, but I said ‘I’m a good girl, I don’t do this. I go to a Christian school’.”

The court was told Ritter then drove her home, repeatedly asking her if she was going to tell anyone about what had happened.

“I remember him saying ‘Nobody needs to know about this. Are you going to tell anyone about this?’

“What do you say in that situation? Gareth was someone I really looked up to. How do you confront that? I’d never been in that situation.”

She said she just wanted to “brush it under the carpet”.

The court heard the woman reported the alleged incident several years later after Ritter’s phone was examined by detectives following an “unrelated matter” that ended with no charges being brought.

Police had found intimate images of a young woman who was under the age of 18. When she was traced, it was the same woman who was sexually assaulted by Ritter.

The court was told the images had originally been screen grabbed with her consent during an intimate video conversation between the woman and another man.

The images had been stored on his tablet, which had been accessed and shared by the man’s housemates, and were later found on Ritter’s phone.

The jury were told Ritter had since pleaded guilty to the possession and distribution of unlawful images, as the woman was 17 at the time the images were taken.

The woman said when she was told her images had been found on Ritter’s phone she decided to report the incident in Cardiff Bay.

The court was told that when Ritter was interviewed by police in December 2022 he denied knowing about the Cardiff Bay flat, and denied taking the woman there. He also told police he had not given her a lift home.

A year later he was interviewed by police again. When asked if he had given a truthful account in his first interview, he said no.

Ritter was granted bail until sentencing on 4 November.