Father tells court how he confronted Helen Turnbull The man challenged Helen Turnbull about the affair she had with his son He said she was a paedophile and said if she was a man he would hit her The man said she was wearing a 'ridiculously short' dress and high heels Ms Turnbull admitted kissing the 16-year-old boy at Teesside Crown Court She has denied three other counts of sexual activity with the boy Helen Louise Turnbull, pictured, was confronted by the father of her alleged victim who warned her that he would have punched her had she been a man A man has told a court how he confronted a teaching assistant in his street after he found out she had been having sex with his teenage son. Teesside Crown Court heard that, full of fury and in front of neighbours, he told 35-year-old Helen Louise Turnbull: 'You are a paedophile and if you had been a man I would hit you, but I'm not going to jail for someone like you.' The 16-year-old boy's father had seen her in her Mini parked 75m from his house, and was incensed when she got out of the car in a 'ridiculously short' dress. He told the jury: 'She had to pull the dress down when she got out of the car. 'All I could think of was "She's dressed in a mini-dress, high heels and a full face of make-up and she's not there to see me, she's come to see my son."' Turnbull, a married mother-of-two, has admitted kissing the pupil but said their secret relationship went no further. She admits one count of sexual activity with a child by a person in a position of trust but denies three further counts which relate to allegations that they had sex and on two separate occasions that she performed sex acts on him in her Mini. The witness told the court he found out from his brother about his son's affair, and he went to the school and police. The teenager was worried about a threat she had made to him about having him 'shot' by a local family when their affair cooled, the father said. 'He was scared to death,' he added. The boy's father reassured him by following in his car as he walked to school with friends. His father then drove home and spotted Turnbull, known at school as Miss Robson, parked in the street. By this stage the affair was over and the police had begun investigating. He recognised her because he had seen her picture on Facebook, he said. She got out of her Mini and said 'something like "Can I have a word with you?"' he said. 'I was fuming, I was mad,' he said. Ms Turnbull, pictured has admitted one count of sexual activity with a child by a person in a position of trust but denies two counts of having sex with the teen in her car and a third count of performing a sex act on him Defence solicitor Ann Richardson asked the boy whether he had exaggerated the scale of the relationship with Ms Turnbull, pictured, which he denied, claiming that he felt 'disgusted about what we did' The father shouted and swore at her and called her a paedophile, to which she replied: 'No, it's not like that.' He shouted her down, recalling: 'I was mad, I kept shouting "You are a paedophile."' He added: 'I think I told her to stop threatening him and leave him alone.' He recalled: 'Because I was shouting, people started coming out of the houses to see what was going on.' The court has heard that Turnbull, from Haswell, County Durham, groomed him by giving him sweets and cuddles, and then embarked on an affair with him in secret meetings at an industrial estate. Earlier, the court was told that both Turnbull and the boy had agreed not to tell their respective friends about their relationship because of the impact it would have on her marriage and her job. Anne Richardson, defending, asked the boy why he broke the agreement and told his friends. Via a videolink, the teenager replied: 'It's lads' craic. 'At the time I was saying one thing to her and when I'm out with the boys, I'm obviously going to be telling them what we have been up to.' Teesside Crown Court, pictured, heard that the boy 'regretted' the effect the affair had on their lives The boy said Turnbull also broke the agreement by telling one of her friends what was going on. He felt 'embarrassed and disgusted' with himself and with her when his father found out, he said. Miss Richardson asked: 'How did you feel about the police becoming involved?' He replied: 'The whole situation shouldn't have happened. 'I regretted what happened, because of the effect it had on my life and on Miss Robson's life.' The pupil denied Miss Richardson's suggestion that he was exaggerating what they had done together. 'I have never exaggerated,' he said. Even if that was the case now, I feel disgusted about what we did.