A man has admitted sending a barrage of threatening messages to a BBC television presenter. Gordon Hawthorn was caught after police released examples of his handwriting in a bid to trace him.

On Thursday, the 68-year-old pleaded guilty to stalking Alex Lovell, who works for BBC Points West. He had threatened to rape her in some of the messages, leaving her in fear and suffering panic attacks.

“I have come to realise I may never be able to forget those two years of fear,” Lovell said.

She had received cards signed “Gordon” since 2012. “Initially, these were infatuated comments about Ms Lovell and they would be received frequently and on key dates, such as Christmas, Easter, Valentine’s Day and her birthday,” the prosecutor, May Li, told Bristol magistrates’ court.

But Lovell said she felt like she “had been punched in the stomach” when the tone of what was in the cards changed and, Li told the court, they became “more sexual and threatening”.

Alex Lovell works for BBC Points West as a news presenter. Photograph: BBC/PA

Lovell told the court: “I opened this one, expecting the usual filth inside only to read that he had made it a New Year’s resolution to have sex with me. I felt like I had been punched in the stomach.”

The court heard that Hawthorn said he had decided he would have sex with her during 2016, even if that meant raping her. Lovell was sent further rape threats, as well as a message indicating Hawthorn had committed rape in the past.

She said she would check every car behind her when she was driving and go round roundabouts twice to ensure she was not being followed. Every car parked outside her home was seen as a potential threat and she increased security. The court also heard Lovell suffered panic attacks last summer due to the stress caused by Hawthorn’s threats.

DC Patrick Prescott of Avon and Somerset police described the messages as “graphic and frightening”.

One of the handwritten messages in a greetings card. Photograph: Avon and Somerset Police/PA

He said officers had a “breakthrough” after issuing a public appeal in March. As well as the Gordon signature on some of the cards, all of them included a pattern of five crosses – one large X and four small Xs around it. A woman who had also been sent cards saw the appeal and recognised the handwriting and cross pattern. “Mr Hawthorn was identified as being the person responsible after DNA came back as a match with two of the cards sent,” the prosecutor told the court.

He was charged with one count of stalking involving serious alarm/distress – an offence under the Protection of Harassment Act 1997.

Hawthorn, from Street in Somerset, admitted sending the cards between 1 January 2016 and 16 March this year. Magistrates told Hawthorn his offending required a “greater punishment” and that he would be sentenced by a crown court judge in January.