Murder victim Caroline Kayll told “white lies” about the illicit relationship she had with a prisoner and the illegal one she started with an underage boy, jurors heard.

The 47-year-old, married at the time to a senior prison officer, started a clandestine relationship with Paul Robson when he was serving at HMP Northumberland where she taught.

She had previously worked as a social worker, a police officer in Cumbria, a prison officer, took on a teaching role behind bars, then moved into a school role, Newcastle Crown Court heard.

She met her husband Ian Kayll in 2002 after she started work at HMP Northumberland, where he was a security manager.

Robson was to claim he had a secret relationship with her during two jail stints, the second of which continued after he was released.

Mrs Kayll remained on good terms with her husband after they separated and they would still meet up every few weeks.

He heard a rumour she had been seen with Robson and said: “I asked Caroline if the rumours were true and she categorically said no and got quite upset I had asked her.”

After Robson broke up with her, she started an illegal sexual relationship with a 15-year-old boy, claiming he was her godson if anyone asked.

Nicholas Lumley QC, prosecuting, acknowledged she told “white lies” about these illicit relationships and that she had made “some life choices that not all of us in this room would make”.

A keen horse-rider, she had two horses at a farm and a border terrier called Boxer who was always by her side.

She owned her own home and pick-up truck but after paying Robson £29,000 in blackmail after he threatened to expose her, her savings were gone.

Robson was convicted of murdering his ex-partner after a trial at Newcastle Crown Court.