A man who sent sexually suggestive messages to a schoolgirl on her BlackBerry phone has been jailed for 21 months.

Paul Martin knew the girl was only 15 but on the day concerned in August last year when he was 49, he sent her a number of increasingly serious texts about what he would like to do with her.

Caroline Wigin prosecuting told Leeds Crown Court  today the messages led up to him trying to persuade the teenager to have sex with him.

The girl was initially non-committal in replies but became distressed and told a friend what he had said in his messages and that led to police involvement.

Martin, now 50 of Well Grove, Brackenhall , Huddersfield, admitted inciting a child to engage in sexual activity.

Jailing him Judge Tom Bayliss QC said: “Offences of this type are by nature predatory and serious.”

There was a considerable age gap but over a period of hours he had sent the girl messages which “became increasingly sexual in nature and culminated in requests for sex.”

“You were grooming her, there is no ambiguity about the content.”

The judge said in one Martin told the girl: “You need a man not a boy” and in another offered to buy the condoms.

“All adults have a duty to behave responsibly towards children, why? Because children lack the maturity to stand up to those who would abuse them. You did not behave responsibly, you acted as a predator, you engaged in a course of conduct that exploited her and was calculated to lead to sexual intercourse.”

He told Martin the fact it did not lead anywhere was not because he had a change of heart but because he was “simply frustrated” in his aim.

The judge accepted Martin’s health was poor and that he had not been in trouble before but said there had to be a jail term. He ordered Martin to register as a sex offender for 10 years.

Gillian Batts told the court in mitigation for Martin that he had heart problems and asthma which would make prison more difficult for him.

She said there had been no previous concerns about his having any sexual interest in young girls. “I would ask you to treat this as an isolated incident.”