The trio broke into the family's home in Stow Road, Magdalen, and smashed the dad around the head with a baseball bat then shut his traumatised children in a bathroom while they ransacked the house.

Det Con Chris Parnham, of Lynn CID, said: "This was a terrifying ordeal for all involved.

"We believe that this was a carefully planned burglary and would appeal for anyone who may know the identity of those involved to make contact."

The children, a nine-year-old boy and his ten-year-old sister, were downstairs while their dad ran a bath upstairs when the intruders got in.

Alerted by the commotion their dad opened the bathroom door only to be confronted by the raiders, one of whom hit him on the head with the bat.

The children were then ushered into the bathroom while the three, who were all masked - one in a Spiderman mask - and dressed in white suits, searched the house for money and valuables.

They left with a large quantity of jewellery including gold bracelets, rings and necklaces – worth around £10,000 in total - and a cream-coloured safe containing nothing of any value.

The children were not physically harmed but have been offered counselling to help them come to terms with what happened.

Their 50-year-old father had to have stitches at Lynn's Queen Elizabeth Hospital.

Officers also want to hear from anyone who may have been offered jewellery for sale in suspicious circumstances or may have found the safe. The offenders also took the hard drive for the house CCTV system and officers want to hear from anyone who may have come across such equipment.

The attack happened at around 7.30pm on Tuesday (7th October).

* Anyone with information should contact DC Chris Parnham at Lynn CID on 0845 456 4567 or alternatively Crimestoppers anonymously on 0800 555111.