A TEENAGE father who allegedly murdered his baby son after taking MDMA today told a court he could be 'heavy-handed' with the tot but was so high he could not remember what happened on the night of his death.

The 17-year-old fought back tears as he told jurors the birth of his son was the "best day of his life", and claimed he would never have intended to harm his seven-week-old son.

He told jurors he had been drinking at a party and had also taken the powdered ecstasy while there but could not remember what happened after leaving until an ambulance was called.

A court has heard the couple, who went to the party with their baby, had returned to their flat in Southampton.

Giving evidence, the teenager, who was just 16 at the time, accepted he had left the flat and told jurors when he returned his girlfriend was "in a right state" as she held their injured baby in her arms.

Prosecutors allege the teenager bit the nose of his baby son before swinging him round, possibly by his feet, causing a spiral break to the tot's leg and a complex skull fracture.

It has been heard the baby's mother did not call 999 straight away, despite the baby being in pain, because she was trying to "protect" her partner.

Winchester Crown Court, Hants, has heard the teenage father and his girlfriend had been to a party in the block of flats she lived in and returned to her flat in the early hours of February 11 this year.

Neighbours told the court they heard a 'blood-curdling' scream from the flat, which sounded like a child in pain.

Giving evidence from behind a screen today, the teenage father told the court: "I partly remember what happened that night.

"We went to the flat where the party was, I remember everyone having a drink and I was talking to people.

"I don't remember exactly what I drank, but there was Corona, Budweiser and spirits like vodka and Captain Morgan's there.

"When I started to drink vodka, that's when I don't remember what happened after that.

"There were drugs at the party, I was offered some Mandy [MDMA]. I thought it was cocaine, but I know now it was MDMA.

"I took some, but I don't remember how much. I don't remember leaving the party, the next thing I remember is I was banging or knocking on the door of [his girlfriend's] flat.

"When I was let in, my girlfriend was sat on the end of the bed with our son in her arms. She was in a bad way, in a right state.

"Our son was not moving, he was stone cold; he looked grey and he was not breathing. I didn't know what to do.

"I was hugging and squeezing him, holding him tight. I just wanted him to make some noise or cry."

The court has heard the teenager, who was 16 at the time of the alleged murder, told a friend 'what have I done?', as he waited to hear of the little boy's condition – although he said he does not remember saying it.

He added: "I never would have intended to do any harm to my son. I always loved him. He was the best thing that happened to me and always will be."

The court heard today the teenage dad was still at school when he found out his girlfriend, who is two years older than him, was pregnant.

He said: "I was calm when I found out she was pregnant, I helped her throughout it and went to all the medical appointments.

"The birth was the best day of my life. I would stay overnight at the mother and baby unit to help out.

"I made up bottles, I picked him up like you would a baby, supporting the back and the head.

"I was known to be heavy-handed sometimes. It runs in my family. On a few occasions my girlfriend would say something to me about it.

"I probably would be quite shitty with her about it because I know what I am doing. I would not squeeze him and I didn't intentionally cause any bruising or injuries."

The 17-year-old father denies murder, while his former girlfriend, the baby's mother, denies neglecting the tot.

The trial continues.