The father of two young children allegedly suffocated by their mother has told a court how their relationship became a "pantomime" as she increasingly used the youngsters to control him.

Paul Donnison, 48, fought back tears as he spoke of his love for three-year-old Harry and two-year-old Elise Donnison giving evidence on the third day of Fiona Donnison's trial.

Their bodies were found zipped up in two separate holdalls in the boot of her car near the former family home in Heathfield, East Sussex, on January 27 last year, Lewes Crown Court heard. Donnison, 45, denies two counts of murder.

Wearing a black suit, Mr Donnison did not look at his former partner, who sat in the dock with her head bowed as he told jurors how he was left in "complete disbelief" when he had returned home from work one day five months earlier to find she had moved out without warning, taking the children with her.

He said he lived a "nightmare" during the months that followed as at first she would not tell him where Harry and Elise were, and then only ever let him see them on her terms.

Mr Donnison said he and his former partner, who he never married but changed her name by deed poll without telling him, attempted to reconcile on several occasions but she would then suddenly change her mind.

If he ever arrived at the house she had rented in Lightwater, Surrey, any later than he said he would, she would not let him in the house and when they made arrangements for him to see the children she would often cancel without explanation.

Mr Donnision said: "It was blowing hot and cold. If I did what I was told things were fine, if I didn't I was told I wouldn't see the children, and so on and so forth. As long as she had control of the children, she had control of me."

He admitted he had started seeing an old school friend named Alison Shimmens but said their friendship was strictly platonic until he knew his relationship with the defendant was definitely over.

"It was refreshing to talk to her," he said. "We were able to talk about things that weren't related to this nightmare that I was living."