A SOUTHAMPTON social worker has been jailed after abusing a vulnerable teenager.

Jonathan Gray, 33, was sent to prison for six months after admitting striking up an affair with the girl.

The relationship only came to light when the youngster thought she was pregnant and told her grandmother, Southampton Crown Court heard.

As he passed sentence, Judge Christopher Leigh QC told Gray: "Anyone committing this sort of offence while in a position of trust and responsibility must inevitably face a sentence of imprisonment."

The court heard that Gray became friends with the girl, who cannot be named for legal reasons. He helped to wash her hair and assisted in her homework.

But the relationship - which they tried to keep secret - grew and developed into heavy petting and kissing.

Peter Savill, prosecuting, said the offence happened when Gray touched the girl over her clothing in a bathroom.

"She was a willing participant," he said. "She felt she was falling in love with the defendant. The relationship developed to the point they had become lovers when she became 16."

The offence came to light when the girl feared she had become pregnant and told her grandmother.

Gray, of Winchester Street, Southamp-ton, had previously pleaded guilty to engaging in sexual activity while in a position of trust. He handed in his resignation to City Council social services bosses on April 10 this year.

Francis Chamberlain, defending, said Gray was of previous good character and the offence was at the 'lower end' of the scale.

"They started off as friends. The relationship developed and they were attracted to each other.

"He was not predatory, despite how wrong his behaviour was. The relationship was consensual, although it has now ended. His pre-sentence report reeks of remorse and he described what he has done as repulsive."

After the case, a Southampton City Council social services spokeswoman said that the employment criteria for their social work staff was constantly updated, but included police checks.

All employees dealing with youngsters are also subject to monthly supervision checks.

She said: "The city council cannot comment on the detail of the case, given our duty to protect the confidentiality of the victim.

"However, we can state that the police were contacted as soon as information came to light and we have worked closely with them during the investigation.

"The safety of children is always of paramount importance. Checking the suitability of people applying to work with children is one of the city council's most important human resource procedures. Equally, we respond swiftly and effectively when we receive any information about the ongoing suitability of our employees."