07/04/2014 13:32 BST | Updated 07/04/2014 13:59 BST

Pistorius: 'I'm Scared to Sleep'

Oscar Pistorius took the stand at his trial today, accused of the murder of Reeva Steenkamp.

Opening with a tearful apology to the Steenkamp family, the athlete spoke of the night he shot his girlfriend, saying: "I was simply trying to protect Reeva."

He added: "I can promise that when she went to bed that night she felt loved. I have tried to write my words on paper a million times to write to you but no words will ever suffice."

The Paralympian sobbed in the dock as he spoke of his unsurprising lack of sleep since shooting and killing 29-year-old Reeva on Valentines Day last year.

Through his tears he spoke of terrifying nightmares, saying: "I'm scared to sleep.

"I wake up, I can smell blood. I wake up to be terrified. I wake up in a complete state of terror to the point where I'd rather not sleep."

The defence trod lightly and the gold medallist spoke predominantly of his happy childhood and successful athletic career, painting a picture of a sensitive soul who had overcome great adversity to become an international sports hero.

But as the week progresses, Pistorius will be expected to answer for the many inconsistencies in his version of the shooting, put forth in the prosecution's case.

So far, four witnesses have given compelling testimonies of a woman's screams on the night of Reeva's death, bringing into question the validity of the athlete's claims that he believed Ms Steenkamp to be an intruder.

Although any suggestion of an argument between the couple has been heavily refuted by the defence, a fifth witness testified to hearing shouting and raised voices between a man and a woman coming from the direction of Pistorius' Silverwoods home, just hours before the shooting.

The blade runner will also be expected to explain why he fired blindly at the locked bathroom door without warning despite passing an exam in firearm competency, which acts a legal prerequisite to owning a gun.

One of his answers in the test, read: "Know your target and what lies beyond."

It appears highly unlikely that prosecutor Gerrie Nel will allow Pistorius to give anything other than definitive responses to these questions after Mr Nel showed his true colours as a compelling and tenacious cross-examiner during his questioning of the first defence witness, Professor Jan Botha.

Under duress from a wilful Nel, Prof. Botha was forced to concede much of his testimony, intended to cast reasonable doubt on the evidence given by forensic experts Captain Christiaan Mangena and Professor Gert Saayman.

The trial adjourned twenty minutes early on account of Pistorius appearing 'exhausted'. His testimony will continue tomorrow at Pretoria High Court.