A former SAS soldier accused of murdering his terminally ill son claimed in court his wife knew the killing was about to take place.

Andrew Wragg said Mary Wragg even agreed to leave their house with their healthy son George while he smothered ten-year-old Jacob with a pillow.

He spoke to Mrs Wragg on the phone hours before the killing, saying he planned to end Jacob's life at their home in Henty Close, Worthing, on return from a holiday.

He said Mrs Wragg replied: "Why wait?"

Wragg's claim contradicts the testimony given earlier in the hearing by his wife, who said she knew nothing of his plan to kill their child.

Jacob suffered from Hunter syndrome, a degenerative disease which had left him deaf, unable to speak and crippled. Few sufferers live past their mid-teens.

Wragg, 37, denies murdering Jacob but admits manslaughter on the grounds of diminished responsibility, claiming it was a mercy killing.

In answer to questions by Michael Sayers, QC, defending, he told Lewes Crown Court yesterday that on the day of the killing in July last year Jacob simply stared at him and looked "fed up with life".

Wragg went out drinking and later rang Mrs Wragg, 41, telling her he thought Jacob had "had enough" and that he had "come to the end of the road ... his quality of life was not worth anything to him. I think he is dead".

He said his wife "totally agreed" and said she was not sure how she could cope watching him deteriorate any further.

He called Mrs Wragg later, telling her he could end Jacob's suffering after his planned holiday, but Mrs Wragg asked: "Why wait?"

Wragg said he told his wife he was not going to do it for himself or for her but for Jacob.

He said: "I did not want him to suffer any more than he had and I wanted him to die with dignity in the place he most loved and was comfortable in."

Wragg told Mr Sayers Jacob was not at death's door but he felt the boy was very uncomfortable and in a great deal of pain.

Wragg telephoned his wife again, telling her: "Get George up and take him to your mother's. It's tonight. Make sure you take George in (to Jacob) and say goodbye."

Wragg said there was no doubt his wife knew what he intended. He said: "She knew exactly what I meant. I would never have done it without Mary's approval."

He did not want Mrs Wragg or George in the house so he could protect them and ensure his wife was not implicated.

Under cross-examination, he denied he was trying to shift the blame. He said: "We both said we would make the decision together.

"I'm telling you, she was completely aware. It would never have happened if she expressed at any time she did not want this to happen."

Carers had testified earlier that Jacob still enjoyed videos, eating and visits. Philip Katz, QC, prosecuting, asked Wragg: "You did not look at it like that?"

Wragg replied: "No sir."

Mr Katz pressed Wragg: "You did this for your own selfish reasons. You did it in drink. You made the decision rationally."

Wragg: "If I was selfish I would have walked away."

The trial continues.