Lance Corporal Trimaan “Harry” Dhillon denies murdering Alice Ruggles and leaving her to bleed to death in the bathroom of her Gateshead flat last October.
He claims he drove 240 miles from his barracks near Edinburgh to retrieve some clothes from her, that they rowed and she attacked him with a carving knife, and that she died when she accidentally stabbed herself in the neck as he tried to disarm her.
Richard Wright QC, cross-examining for a second day, said to Dhillon: “You broke in, caught her unawares, before she had time to react. Is that what you did?”
The 26-year-old signaller with the 2 Scots, who had taken courses to join the Special Reconnaissance Regiment, denied it.
Mr Wright said Dhillon was 6ft 1in and weighed twelve and a half stone, while Miss Ruggles was just 5ft 2in and weighed three stone less.
Mr Wright said the 24-year-old Sky employee died after the knife was drawn against her neck six times.
Dhillon denied it, saying: “If you are that confident, why not give me a lie detector then, sir?”
Judge Paul Sloan QC said at Newcastle Crown Court: “That’s not how we conduct proceedings.”
Dhillon did not know how Miss Ruggles suffered bruises to her chest, saying if he was so “clever”, he would have an explanation.
Mr Wright said: “I don’t suggest you are clever. I suggest you are a liar.”
Dhillon agreed he felt “heart-broken” and “devastated” having seen his ex with the knife in her neck, which he claims happened when she lunged at him from the bathroom floor.
Mr Wright said despite having those feelings, Dhillon did not ring 999 to summon help for the woman he claimed to love.
Dhillon claimed he tried to ring an ambulance, but said he panicked.
Mr Wright said Dhillon claimed to be the peace-maker, trying to calm Miss Ruggles down, that it was Dhillon who was attacked with the knife, and that it was him who was fighting for his life.
Mr Wright said Miss Ruggles suffered 24 injuries, while Dhillon had “not a single one from the knife”.
Mr Wright asked: “Did you ever consider you had done the worst job ever at protecting somebody from themselves?”
Dhillon replied: “Yes, I have done the worst job, yes.”
Mr Wright said: “Alice wanted to live and she fought for her life that afternoon and you killed her.”
Dhillon replied: “No, I did not kill her.”
Jamie Hill QC, defending, asked: “You said you did not know how you felt afterwards. How do you feel now?”
Dhillon replied: “When I was in prison, sometimes I would sit up in the night time and you know when people say ‘It’s all a bad dream’, it’s all going to go away. I’m going to wake up one day and none of this will have happened.
“On that day I didn’t know what I was doing.
“That was the shortest drive from Newcastle to my camp.
“I don’t even remember that drive.”
The trial continues and the jury has been told by the judge that he expected they would start deliberations on Wednesday.