A Bulgarian couple chained their seven-year-old boy to the kitchen sink to prevent him from misbehaving while they were at work, the daily Trud reported.

Social services in Bulgaria had to intervene after being notified by neighbours in the south-eastern town of Gotse Delchev, who heard the boy's father boast about how he was managing to control his son, the paper added.

According to the report, his parents began chaining the boy, Ilko, at the beginning of the summer holidays.

The report said Ilko was bound by a four-metre chain to the sink when his mother, a cleaning lady, and his father, who worked in metallurgy, left the house.

The chain was long enough to allow him to open the fridge and reach their terrace - but not to go to the toilet.

His only company was the family's dog Bucky - ironically, the dog was able to roam freely.

The child told social services that he was being punished for misbehaving.

His mother said her husband "was afraid his son would turn into a criminal," Trud reported.

Ilko has since been brought to an orphanage.

Social services were due to rule within 10 days whether he could be returned to his mother, who has promised to leave her husband.