The unnamed man dived into the River Taff in Blackweir on Tuesday at 1505 BST after spotting his girlfriend's 10-year-old son and friend in difficulty.

The 40-year-old, who has not been named, managed to reach the youngsters and pulled them from the water.

He hauled the children to the riverbank where they were dragged to safety by his girlfriend.

Both youngsters were unharmed by the incident.

However, it is believed, that as the woman tended to the children, the council worker got into trouble and went under the water.

Life support machine

The emergency services arrived within minutes and two police officers and a paramedic pulled him from the water.

He was given first aid treatment before being admitted to the University Hospital of Wales, Cardiff.

He was placed on a life support machine but died on Thursday.

The coroner has been informed of his death.

A spokeswoman for South Wales Police said they were not treating his death as a criminal matter but were carrying out inquiries on behalf of the coroner.