Ian Stewart had a “very happy” marriage and was “caring and gentle” towards his wife Diane, a court heard today.

The 61-year-old, who is originally from Letchworth, is accused of killing Diane Stewart, 47, at their home in Bassingbourn in 2010 - six years before he killed Royston children's author Helen Bailey.

The cause of Diane's death was recorded at the time as sudden unexplained death in epilepsy - and police investigated the case after a jury found Stewart guilty of 51-year-old Ms Bailey's murder in 2017. He is currently serving a life term with a minimum of 34 years in prison.

Dr Andrew Pullen told jurors at Huntingdon Crown Court that he first met Stewart in the 1980s when they were both students at the Cambridge University computer lab.

He said they and their partners socialised together as a group of four, adding that the couple became “our best friends in fact”.

Asked by Amjad Malik QC, defending, about Stewart’s manner towards Diane, the retired product development manager said: “Caring and gentle.

“They were both very gentle with each other. They would work together as a nice team.

“If we went round for dinner, Ian and Diane would be in the kitchen preparing together – just a really nice couple, very caring, just lovely people.”

He said that at Mrs Stewart’s funeral, the defendant appeared “shocked”.

“He was just very numb,” Dr Pullen said.

Asked by Neil King, prosecuting, about Stewart’s conviction for the murder of Ms Bailey, whose body was found in a cesspit with her dog Boris, Dr Pullen said: “That’s a verdict of the trial.

“I find it very hard to believe.”

Mr King said: “There was nothing about Ian Stewart that led you to believe he was capable of that, was there?”

“No,” replied Dr Pullen.

Dr Pullen’s wife, Sallyann Pullen, said the Stewarts’ marriage “seemed very settled, very stable, very happy”.

“I never saw them arguing or disputing anything, just a very nice relationship and a very nice family unit,” she said.

She agreed with Mr King that, when Stewart was in a relationship with Ms Bailey, they seemed “very much in love” and she did not see them arguing.

Stewart denies the murder of his wife.

The trial continues.