A 47-year-old man from Kent, UK, who was jailed for nearly beating his one-month-old son to death was reportedly beaten up by his fellow inmates who used "a sock filled with tuna cans" and metal bars to assault him.

The man, identified as Tony Smith, was imprisoned after he was found guilty for assaulting his baby son so badly that his legs had to be amputated. Smith was jailed along with the baby's mother, 24-year-old Jody Simpson, according to the Daily Mail.

Smith and Simpson have been sentenced to 10 years of imprisonment for a "series of spiteful assaults" on their baby son. Authorities had released multiple shocking pictures of the squalor inside the couple's flat in Maidstone, Kent.

Although the couple had initially denied causing serious physical harm to the child, they were eventually found guilty less than an hour after a jury retired to consider verdicts, reports state. Medical experts at the Maidstone Crown Court said that the baby was seconds from death with septicaemia when he was brought to the doctors at 41 days old.

Reports state that Smith's attackers were two inmates at Swaleside Prison on the Isle of Sheppey in Kent. They are believed to have attacked Smith after he was wrongly housed in the wing for vulnerable prisoners, according to The Daily Star.

Smith reportedly sustained multiple injuries after the incident, including a fractured eye socket, a broken jaw, and broken ribs.

A prison source, while talking to The Star, said: "They came into contact with Smith and held him hostage in his own cell for four hours. During that time they tied him to a chair and attacked him with a sock filled with tuna cans and metal bars. They also stamped all over him. Prison guards managed to get them off in the nick of time – he's lucky he didn't die."

Prison authorities have reportedly launched an investigation into the attack and how it was allowed to occur inside the cell.

A prison service spokesperson said: "Staff resolved an incident involving three prisoners at HMP Swaleside on 7 August. The incident has been referred to the police so it would be inappropriate to comment further," according to The Sun.