Nicholas Halling, 36, of Dunstable, Bedfordshire, who had convictions stretching back 25 years, made Deraye Lewis’s life intolerable. He referred to him as “black bastard” and even wrote the word “nigger” in felt pen on the boy, who was forced to repeat it back to him “like a terrified parrot”.

When the toddler was taken to hospital on January 1 last year, already dead from internal injuries, medical examiners found 73 marks on his body, some of which could have been cigarette burns. He also had a perforated eardrum and a brain injury.

His mother, Donna Humphrey, 22, was also a victim of Halling and was unable to protect the child she loved.

In a statement released by Thames Valley Police she said: “Nicholas Halling is not the only person who will serve a sentence for his crime. Everyone who loved and cared for my son will serve a life sentence.”

Halling, a drug dealer with convictions for theft and attempted burglary, denied murder and the assault on Ms Humphrey. Mr Justice Hughes said that he had habitually treated the little boy with “contempt, hostility and some violence over a period of at least a year”. He jailed him for life yesterday and Halling will have to serve a minimum of 20 years.

Timothy Raggatt, for the prosecution, told the jury at Luton Crown Court that Deraye died after his lower intestine was split open. The boy spent a day being sick before dying in his mother’s arms as he slept at night.

Pathologists said that the fatal injury was probably caused by a heavy punch with a clenched fist, a kick with a shod foot or possibly the child was stamped on. It could not have been accidental, they said.

The social services department had been told about Halling’s racist abuse but Ms Humphrey denied it. She left Halling once after making a complaint to police but she later retracted it and returned to him, unknown to social workers.

In the hours before Deraye died she called police to her home in Bletchley, Buckinghamshire, after Halling assaulted her. When police arrived they saw the boy crying but were powerless to act because no complaint had been made on his behalf and Ms Humphrey retracted her complaint.

Halling was also sentenced to 18 months for actual bodily harm against Ms Humphrey.

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