A tearful Oscar Pistorius has apologised to Reeva Steenkamp’s family, telling the court he had “terrible nightmares” since killing his girlfriend and often woke up smelling blood.

Stammering and with his jaw trembling, began his testimony on Monday by saying Steenkamp “felt love” before he shot her dead in what prosecutors say was premeditated murder and he says was an accident.

“There hasn’t been a moment since this tragedy happened that I haven’t thought about your family. I wake up every morning and you are the first people I think of,” he told the Pretoria court.

“I can’t imagine the pain and emptiness I caused you and your family. I was simply trying to protect Reeva. When she went to bed that night she felt loved.”

In the tribunal Steenkamp’s mother June, flanked by other relatives, stared at him stony-faced during the apology.

She has sat through weeks of gruesome evidence, including brutal images of her dead daughter.

Pistorius told the court he had been on anti-depressants and sedatives since killing Reeva and that he is “scared to sleep”.

“I have terrible nightmares about things that happened that night, where I wake up and I can smell blood,” he said.

He also said he has been on anti-depressants since the shooting.

Pistorius had his head in his hands in court.

Pistorius has cut a lonely figure since his trial started on March 3, saying little since his “not guilty” plea besides the occasional “yes, milady” to Judge Thokozile Masipa.

How the double amputee known as the Blade Runner will hold up during the state’s cross-examination may prove a turning point in the case.

How the double amputee known as the Blade Runner will hold up during the state’s cross-examination may prove a turning point in the case.

In the five weeks since the trial began, Pistorius has appeared fragile and annoyed, frequently crying in court and being physically sick when the gruesome details of Steenkamp’s death were discussed.

Pistorius says he shot his girlfriend through a bathroom door after mistaking her for an intruder.

The judge adjourned the trial a week ago after a judicial assistant fell ill. Media interest in the case has slowly been declining, but Pistorius’s testimony is likely to grab global headlines.

The court was forced to adjourn for the day ahead of schedule after defence lawyer Barry Roux said his witness was exhausted by a lack of sleep and the day’s ordeal.

“Well he does look exhausted, he sounds exhausted,” said Judge Thokozile Masipa, granting the defence an adjournment until Tuesday.