A 40-year-old man with a foot fetish for young girls has been jailed for nine months after secretly taking photographs of a pupil from Watford Grammar School for Girls.

Martin Rodriguez breached the conditions of a sexual offences prevention order (SOPO) by snapping the oblivious girl in St Albans Road, Watford, on the afternoon of October 23.

Rodriguez had been drinking all day when he armed himself with his camera out took 18 pictures of the girl without her knowledge.

Rodriguez, who gives his occupation as a photographer, is on an order until 2014 prohibiting him taking photographs of anyone under the age of 18.

The order was imposed after Rodriguez was convicted of a public nuisance offence after taking pictures of young girls' feet.

He has breached the order before and in April last year was jailed for eight months after police found photographs of girls at his home in Queens Road, Watford, following an appeal on Crimewatch.

There is no treatment for Rodriguez's condition, but Alex Goudie, defending said there was a suggestion he may have a form of Asperger's Syndrome.

Rodriguez, now of The Ridgeway, Watford, was jailed for nine months at St Albans Crown Court on Friday after admitting breaching the order.

Judge Plumstead said "thank heavens" the girl was unaware the pictures were being taken.

"She and her family would be scared witless if they had been aware," he said.

Rodriguez has two previous convictions for "non genital" sexual assault in connection with his fetish for "the lower limbs of young girls".

Turning to Rodriguez, Judge Plumstead said: "You are going to go to jail for nine months.

"In this case I am dealing with a man who has a compulsive interest in under-age girls.

"That interest has so far only taken the form of featuring their feet and lower limbs.

"In the past there has been sexual assault. Contact without a consent with little girls quite unaware of his sexual agenda.

"This perverse interest has led to him to having two convictions for sexual assault and a sexual offences prevention order being made prohibiting him taking photos of young girls.

"He has breached that order for the second time and Mr Rodriguez must understand a second breach is more serious than the first, a third breach is more serious still."

Rodriguez was warned if he continued to take pictures of young girls a sentence for public protection could be passed - effectively a life sentence until the authorities are satisfied he poses no risk.

Judge Plumstead said: "If he will not desist from contact with young girls I would be concerned he may be dangerous and need to impose a public protection sentence.

"I hope that's clear. I want that to get through to you, Mr Rodriguez.

"You must battle your demons because if you lay a finger on and under age girl in a sexual way you must accept a really severe punishment."

Ninety-one days on remand were ordered to count towards the sentence.