Frances Inglis gave her son Tom a lethal heroin shot.
A mother who lethally injected her disabled 22 year-old son with heroin has told a UK court that she had "no choice" but to give her son the drugs.

Knowing that she would be charged with murder, and that what she did was against the law, did not stop Frances Inglis from going ahead with the plan.

Her son Tom was in a "living hell" after becoming disabled with serious head injuries when he fell out of a moving ambulance in July 2007.

The Times reports Mrs Inglis told the jury her son still had "emotions, although he couldn’t express them in words".

She said although an option available could have been to remove her son's feeding tube, she felt that to be too cruel. Instead she researched on the internet how to obtain heroin, and what dose would be likely to kill him.

She also frequented injecting rooms around London in a bid to find a seller of the drug.

"I believed it would have been Tom’s choice to have been allowed to die rather than have the intervention to keep him alive," she said.

"I felt he lost his life when he came out of the ambulance. I felt that I was helping, releasing him.

"I don’t see it as killing or murder. The definition of murder is to take someone’s life with malice in your heart.

"I did it with love in my heart, for Tom, so I don’t see it as murder.

"I knew what I was doing was against the law. I don’t know what name they would call it but I knew that the law would say it was wrong."

The court heard she waited until she had some time alone with her son in the nursing home and injected him with the drug in both thighs and this arms. She said he died peacefully, and in her arms.

She sobbed as she gave evidence: "I had no choice, I had no choice. I would have chosen anything else. I would have done anything else.

"It is not that I wanted to do it, I had to. I couldn’t leave my son there.

"It is not an easy decision to make or something that anybody would want to do. I had no choice."

Tom Inglis was living in a nursing home and receiving care for his significant brain injuries but his mother felt his opportunity for improvement was limited.

Evidence was tendered to the court which said otherwise: one treating doctor said he could forsee a time when Tom was able to care for himself or start his own business.

Friends told the court that although Mrs Inglis was "the pillar community" and of excellent character, her son's accident had changed her.

Mrs Inglis told the court she could think of nothing else but her son's pain and the "terror" she saw in his eyes.

The trial is continuing.