A sex offender “bombarded” a child minder with explicit text messages after seeing her in a superstore, York magistrates heard.

David Victor McEwan, 61, posed as a teenage boy aged 15 or 16, as he pestered the young woman, who was a complete stranger to him, said Colette Dixon, prosecuting.

He targeted her after he saw her put her business card on a noticeboard in a Tesco store.

She hoped the card would attract parents wanting to find a safe guardian to care for their children.

Instead, McEwan took the card and used the telephone number on it to “bombard” her phone with his “extremely explicit” text messages. He ignored her repeated texts back to leave her alone and she went to the police.

She told them she had to act “not just for myself, but also in case this man poses as a teenager again”.

The text messages had upset her so much that every time she saw a teenage boy aged 15 or 16 she wondered if he was the source of the sex messages, and she was now very cautious about advertising her business.

It was the second time McEwan, of Goose Lane, Sutton-on-the-Forest, had offended women by his sexual behaviour. In 2003, he was fined for indecently exposing himself with intent to annoy a woman.

McEwan pleaded guilty to sending indecent text messages between August 1 and August 7, 2010. Magistrates warned him they were considering locking him up and adjourned sentence for a pre-sentence report until September 27.

Mrs Dixon said the Crown Prosecution Service would urge magistrates to make a restraining order on him when he is sentenced.

McEwan was released on bail on condition he does not contact the child minder.

“I want to apologise to the court and to the lady concerned,” McEwan said. “I am full of remorse and deeply ashamed of myself and I ask the court’s forgiveness.”

His solicitor, Damien Morrison, said McEwan had voluntarily sought help from a community mental health team.