Detectives are able to investigate new lines of enquiry after receiving a “positive response” to a renewed appeal into the disappearance of Amanda Duncan, who was last seen 20 years ago.

The 26-year-old left her three-year-old son Jamie with her parents at about noon on July 2, 1993 and her nine-month-old son, Damien, with a babysitter at her home in Balliol Close, Woodbridge.

She then travelled to the Portman Road area of Ipswich where she was working as a prostitute. She was reported missing the following day when Miss Duncan’s sister visited her home and found Damien alone.

Suffolk police renewed their appeal for information at the beginning of this month.

Detective Chief Inspector Tracey Little, from the Joint Norfolk and Suffolk Major Investigation Team, is overseeing the case.

She said: “Following the anniversary appeal into the disappearance of Amanda Duncan, Suffolk Police has received a positive response from members of the public who had information to offer us and the calls we have received have resulted in new lines of enquiry.”

Miss Duncan was described as white, 5ft 7ins tall, of medium build with fair, shoulder length hair. She had a distinctive heart-shaped tattoo on her upper left arm.

Before starting work on the night of July 2, she visited a house in London Road, Ipswich, at about 11.10pm.

She was taken to Portman Road by car and dropped off at 11.30pm but never returned to the house, where it is understood she was trying to buy drugs.

She was seen speaking to the driver of a dark Ford Sierra at about midnight in Portman’s Walk. Appeals were also made to trace a second vehicle, a red Ford Orion, in Portman’s Walk at 11.50pm.

The Orion was driven by a white man aged between 25-30.

Police are still calling for anyone with information to come forward by calling 101 or Crimestoppers on 0800 555111.