A woman who ill-treated three boys she temporarily looked after - making one of them clean his teeth with dog excrement smeared on the brush - has been jailed for 20 months.

Stephanie Chibnall was told by a judge he could not ignore the "depraved and sadistic" toothbrush incident.

Maidstone Crown Court heard how Chibnall would also discipline the children by beating them with sticks.

The 45-year-old, of St Patrick's Gardens, Gravesend, denied three charges of cruelty to a person under 16, but was convicted at a trial in September.

Anthony Prosser, prosecuting, said one of the boys told his mother he had hidden some blades because he wanted to kill himself.

He said he had wanted to tell his mother that Chibnall had hit him with a stick on his knee and upper leg because he did not have any homework.

"i cannot ignore the lasting damage you are likely to have caused to these three young boys..." – judge david griffith-jones qc

An investigation was launched. Teachers at the boy's school noticed he had a large bruise from his left knee to the hip and described it as looking like he had been in a car crash.

They thought it was more severe because of a medical condition he had. The boy said he had fallen over in the playground.

Teachers of one of the other boys saw he had a bruised face and swollen and cut lower lip. He at first claimed he had been hit by a swing but later said Chibnall had hit him in the mouth.

Mr Prosser said Chibnall was angry because a toothbrush was dirty.

When one of the boys did not own up, suspicion fell on him. "She made him go out into the garden and smear dog poo on it," he said.

Chibnall emphatically denied assaulting the boys. She said she may have made them stand in the corner with their hands on their heads to discipline them.

Judge David Griffith-Jones QC said Chibnall's intentions may have been laudable, but her methods were "inappropriate, excessive and potentially very damaging".

One boy needed hospital treatment after he was struck by her. When she thought another boy had taken her cigarettes, she hit him with an electric fly swat.

"These three boys were not just very young, they were vulnerable," said the judge.

He recognised, he said, that she had experienced traumas in her life, including the death of her husband in 2007 after a long illness.

"You were left in a state where you could not control your emotions and responses," he continued.

"It is apparent you are deeply ashamed of your behaviour, although you remain in denial about the physical abuse, which is a feature with which you will have to be helped.

"It has to be said it is a tragedy you did not seek the help you needed with sufficient vigour. It is a tragedy those close to you did not identify you needed help and recognised you were unable to manage and, most importantly, that they did not intervene to stop the abuse you were delivering to the boys."

For reasons that were not clear, Social Services did not spot the problem and intervene sooner.

"An immediate prison sentence is demanded," said Judge Griffith-Jones. "I cannot ignore the abuse in these offences.

"I cannot ignore, on the face of it, the depraved and sadistic feature involved in the incident with the toothbrush.

"I cannot ignore the lasting damage you are likely to have caused to these three young boys."

Chibnall was banned from working with children.