An admitted paedophile who waged an extensive stalking campaign against Radio 2 DJ Sara Cox has been jailed for 16 months.

The maximum sentence Tony Collins could have faced for harassment was six months imprisonment.

Because of his early guilty plea he was sentenced to four months with 12 months consecutive for possessing and making indecent images of children.

Judge Martin Joy was critical of the Crown Prosecution Service for not prosecuting the 50-year-old sex offender for breaches of restraining orders and sexual harm prevention orders - the maximum sentence for which is five years imprisonment.

The judge had called for a “full risk assessment” on Collins in April.

A psychiatrist had suggested a further assessment for consideration to be given to a hospital order under the Mental Health Act but Judge Joy decided the case should proceed to sentence.

Collins, who has previous convictions for harassment, claimed he found out Ms Cox’s London address by paying £17 on the internet. He declared he found her sexy.

Using her married name of Cyzer, he wrote letters to her in distinctive green felt pen, as well as writing to her husband Ben at his workplace.

When arrested, Collins was found to have indecent pictures of young children at his home in Afghan Road, Chatham.

He admitted harassment and possessing and making indecent photographs of a child.

Prosecutor Mary Jacobson told Maidstone Crown Court Collins sent distressing letters to the well-known radio broadcaster and her husband.

Ms Cox, 42, had received a letter from him more than a year before she complained to the police, but did not take any action.

The envelope sent on January 24 this year contained two letters and a photo of himself. She informed the BBC.

In the letters he spoke of being lonely and his “extensive criminal record”, adding he was psychologically disturbed and schizophrenic.

“What would you do if you lost your health?” he asked. “I am lonely. I live in a bedsit for poor people. I am unhappy.

“My name is Tony Collins. I am 49. I have green eyes. I know you are married to Ben Cyzer and he is a successful man.

“I know you are an ambassador for Centrepoint homeless for London. Don’t feel sad for me. I listen a lot to Radio 2 and your show.”

“I am lonely. I live in a bedsit for poor people. I am unhappy" - Collins wrote letters to Sara Cox

Miss Jacobson said Collins mentioned Ms Cox’s dog by name and her love of horses. “They are psychic,” he wrote. “They know our feelings.”

He gave his mobile phone number and address.

“This was causing concern given the reference to knowledge of her husband,” said Miss Jacobson.

He asked to be invited to the BBC studios and told her: “I apologise for writing to your home address. I got it for £17 on the internet.”

A fresh order restraining Collins from any contact with Ms Cox or her family and a sexual harm prevention order, both indefinitely, were made.

Miss Jacobson said Collins, who has served five-and-a-half months - the equivalent of 11 months - on remand, said in a letter Ms Cox was “sexy and attractive” and “a fantastic woman of 42.”

He gave her date of birth, declaring: “I have done my research online.”

“It clearly caused her concern,” said Miss Jacobson.

On February 7, Mr Cyzer received a letter from Collins at his work. It contained a scientific diagram involving cancer analysis.

He addressed him as Ben and asked him to contact him on his mobile phone. The envelope contained a photo of Ms Cox carrying a baby.

“When he told his wife, she was understandably much more scared, is how she phrased it,” said Miss Jacobson. “At that stage, the police were contacted.”

When arrested at his home on February 10, Collins said: “I am guilty of the offence you are talking about.

Others letters which had not been sent to Ms Cox were found, along with cuttings and pictures.

There was also a picture of a BBC visitor’s pass and a document about farming, which he said he was thinking of sending to her father as he knew he was a farmer in the north.

Collins admitted his behaviour amounted to harassment. Ian Dear, defending, explained: “He basically says ‘I want to be on the news’.”

Miss Jacobson said Collins also had three indecent images of children in the second highest category of seriousness and eight in the least serious category.

Collins had eight convictions for 13 offences dating back to 1991, including harassment and breaches of restraining orders.

In one offence he befriended a 13-year-old girl and administered poison to her to sedate her to have sex with her. He was jailed for 18 months.

On one occasion he followed a nine-year-old girl from school to her home and left her a note with his mobile phone number and address on it.

He had also befriended two girls, aged 15, who visited his home to drink and smoke.