Crown Court heard how Osita Onwugbufor, aged 47, gouged a letter W into his eight-year-old son Mezie's scalp.
Onwugbufor beat the Down syndrome boy over the head with a belt and also beat one of his other sons.
Onwugbufor, of Church Manorway, Abbey Wood, was given a four-year jail sentence by Judge Hubert Dunn last Friday.

He had been found guilty of child neglect and two charges of common assault.
There is some suggestion the carving was done as part of a witchcraft ritual.

The judge told him: "Your son was a seriously disadvantaged child who was subjected to quite appalling treatment.
"In my judgment, the cruelty in this case was of a most serious nature."

Nigerian-born Onwugbufor had custody of his three sons, then aged eight, 10 and 11, but their divorced mother, Sade Gbadamosi, saw them regularly.

On June 19, 2004, when their mother arrived to collect her sons for the day, Onwugbufor refused to let them go.
A row began and both parents called the police.
When they arrived, an officer spoke to 10-year-old Ebele, who revealed his father had punched him and beat him with a stick the week before because he was late home from football.

The boy said the beating had broken the stick and left him with a bleeding mouth.
Police immediately arrested Onwugbufor, took the boys into protective custody and handed them to their mother for safekeeping.

Later the same day, she took her sons to the barber to have their hair trimmed.
As Mezie was having his hair cut, the barber found the injury to his scalp.
Onwugbufor, who was on police bail, subsequently tried to snatch the boys from their schools one afternoon but was stopped by police.
On evidence from Ebele, Onwugbufor was also charged with beating his Down syndrome child.

He consistently denied gouging the letter W into Mezie's head.
When he was sentenced last week, he again protested his innocence and claimed all three boys were in "fine health" when their mother collected them on June 19.

picture here - http://www.thisislocallondon.co.uk/whereilive/lewisham/display.var.1267783.0.father_gouged_letter_w_into_sons_scalp.php