A four-year-old boy suffered the kind of head injuries normally seen on battered boxers, a court heard.

John Smith received a number of blows to the head which caused a fatal brain haemorrhage, said paediatrician Professor Jo Sibert.

He told Lewes Crown Court more than 50 bruises plus four adult bite marks pointed to abuse.

Bruising round the boy's head was probably from more than one blow. It appeared John had been hit and injured "like an unfortunate boxer."

The blows, he said, were delivered with a lot of force and he described the child's death as horrific.

The boy was being adopted by Michelle and Simon McWilliam, who deny cruelty and insist John self harmed.

The boy had spent six months at the couple's home in Gardner Road, Fishersgate, Southwick, before his death on Christmas Eve, 1999.

Prof Sibert said he studied a report dated August 23 which said John had self abused and had suffered a carpet burn on his face, facial bruising and bruising down the spine.

Prof Sibert said: "I would have made a clear diagnosis of non-accidental injury or child abuse."

A bruise above the right ear, he said, was not usually caused by anything but a blow - "I would have been extremely concerned."

Prof Sibert said reports of an injury to the boy's penis suggested sexual abuse. He said he had never come across such a self-inflicted injury on a child.

Injuries seen in November included a black eye and two linear bruises underneath, patterns that suggested a slap with a hand, he said.

A bald patch on the boy's head was unlikely to have been self-inflicted and was probably the result of abuse, he said. It could have been caused when the boy was being held as he was abused. He added: "It would have been extremely painful."

Adult bite marks on the body were also indicative of abuse and would have caused the boy trauma. The splitting of a flap of skin under the top lip was probably not caused by accident, he said.

Cross examined by Lord Thomas, for McWilliam, Prof Sibert said he could not exclude the possibility some of the boy's injuries were the result of self harm.

Prof Sibert agreed adoptive children often suffered trauma but, he said, extreme self harm as seen in this case was "outside my experience."

The trial continues.