She also kissed him on the mouth and put his hand down her pyjamas

A woman babysitter who forced a 13-year-old boy to carry out sex acts on her at a onesie party before sending him a number of explicit Facebook messages was spared prison but put under a night-time curfew.

Mary-Ellen Mooney rubbed the boy's thigh and kissed him before putting his hand down her knickers while babysitting him, a court heard.

Mooney committed the sex acts on three separate occasions during an evening looking after the boy - who, each time, dashed up the stairs to tell a pal who was playing computer games what had happened.

Mary-Ellen Mooney rubbed a boy's thigh and kissed him before putting his hand down her knickers while baby sitting him, a court heard

Then two days later she sent him Facebook messages where she referred to the youngster as 'babe', saying that she had 'a real soft spot' for him and believed the boy had 'a hidden talent.'

It emerged that Mooney was attacked by an incensed family member of the boy at her home after the offences came to light, with the perpetrator being convicted.

Mooney was arrested and charged with two offences, which she initially denied before finally admitting her guilt on what was meant to be the morning of her trial.

Her victim, who cannot be named for legal reasons, had already come to court ready to give evidence against his babysitter at the trial, which was scheduled to take place last month.

It emerged that Mooney was attacked by an incensed family member of the boy at her home after the offences came to light, with the perpetrator being convicted

Mooney, now aged 19 years, looked on from the court dock and showed no emotion as she was handed a suspended jail sentence.

The offences were committed at the boy's home over the weekend of January 10-11, when Mooney was aged 18.

Graham Smith, prosecuting, said she found her victim and his friend in his bedroom playing computer games when she arrived to babysit. Noticing they were both wearing onesies, she suggested having a onesie party and went back home to change into hers.

When she returned she suggested watching a film downstairs.

Mooney's victim agreed to come and watch with her, but the friend stayed upstairs in the bedroom playing video games.

Mr Smith told the court: 'She started touching him on his upper thigh. He asked her to stop, which she did, before pretending she had been winding him up.

'He started to become sexually excited. He got up and went upstairs to the bedroom. As she followed, she said she was winding him up. They went back downstairs.

'She put on the music channel and started dancing. She then sat on top of him, straddling him face to face. She then kissed him on the lips. He described it as open and closed mouth, but with no tongues. He didn't feel like he wanted to kiss her back.

'She got up and went to get a drink. The complainant went upstairs and told his friend what had happened. [The friend] said it was disgusting.'

The boy came back downstairs and found Mooney had by now changed into pyjamas, Mr Smith said.

He said: 'She sat in front of him with her back to him. She pulled his right arm around her body, as if to hug her.

'She took his right hand and placed it inside her pyjamas. She took her hand out, leaving his there, before placing her hand over his through the clothing.

Two days later, he said, Mooney sent a number of sexually explicit messages to the boy through Facebook.

The court was told the messages read: 'We should meet up, just me and you. Keep it hush hush - don't tell [the friend].

'You are fairly mature for your age and you're not bad looking. I have got a really soft spot for you, babe. I think you have a hidden talent. I think you could handle me.

'You are going to take control of me and show your dominant side.

'It isn't about size, it's the way you use it.

During the exchange she also said she 'could get into trouble' if anyone else read the messages.

The offences were committed at the boy's home over the weekend of January 10-11, when Mooney was aged 18

Mooney was arrested nearly a week later after the boy's family complained to the police. In interview she claimed the boy said he wanted to smoke cannabis, before saying he had instigated the sexual activity, Mr Smith told the court.

Sophie Murray, defending, said: 'She has had to cope throughout her young life with her personal circumstances of very poor parenting. There was an absent father and her mother an alcoholic. She was the carer within the family for her mother, whose alcoholism at times was very bad. She subsequently died when she [Mooney] was 13.

'She hasn't, despite that very dysfunctional upbringing, until now committed any other crimes. She has had jobs and hasn't sought reliance on the State for income.'

She said Mooney had held jobs at a branch of Starbucks and at a telemarketing company but had lost both of them since her offending came to light.

Miss Murray said: 'She has a capacity to work and look after herself and to prove that she can be a contributing member of society.

'She has accepted her guilt. She is deeply shameful and guilt-ridden about what has happened.'

She said Mooney should have any jail sentence suspended so that she would benefit from one-to-one courses aimed to teach defendants appropriate sexual behaviour - something Miss Murray said is not made available to serving prisoners.

You were trusted to be the babysitter. You clearly knew what you were doing was wrong. Judge Karen Holt, sitting at Amersham Crown Court

Miss Murray added the probation service had raised concerns over her mental health, with experts saying she had difficulty recognising boundaries on sexual matters.

Judge Karen Holt, sitting at Amersham Crown Court, said: 'You were trusted to be the babysitter. You clearly knew what you were doing was wrong.

'I don't have a victim impact statement but there is reference in the papers I have read to [the boy] becoming withdrawn after this happening.

'I have listened very carefully to everything said on your behalf - I don't find this an easy case.

'The law reflects the seriousness of this abuse of trust on a child so young. As far as you are concerned, it is right I take into account the background - you have a sad background. You have not got into trouble despite your poor parenting.

'Bearing in mind your age and lack of previous convictions, your case doesn't meet the criteria for any form of imprisonment for public protection.

'A custodial sentence is appropriate. I have spent some time, bearing in mind all the circumstances, on whether that has to be an immediate custodial sentence. I am just about persuaded I don't need to send you to prison today.'

On count one, of causing a child to engage in sexual activity, Mooney was given a two year prison sentence suspended for two years. She must be supervised throughout the two years, undertake 100 hours of unpaid work and be the subject of a three month curfew between 7pm and 6am.

On count two - of inciting a child to engage in sexual activity, relating to the Facebook messages - she was given a concurrent 12 month sentence, which was suspended for two years.