The 1974 mystery of the headless body at Cockley Cley was given national exposure last night with a report on the BBC's Crimewatch programme which revealed for the first time that the woman might have been through childbirth.

The 1974 mystery of the headless body at Cockley Cley was given national exposure last night with a report on the BBC's Crimewatch programme which revealed for the first time that the woman might have been through childbirth.

Norfolk Police reopened the investigation into the 34-year-old case last December in a bid to finally identify the young woman who was found decapitated and abandoned by the side of a lane in the village near Swaffham.

Det Insp Andy Guy travelled to London yesterday to appear live on the programme at 9pm to appeal for relatives of women who went missing at the time to come forward. During the 10.35pm update he said he was “pleased” with the 30 calls that had come in, providing 12 names of women, some of them new.

The section also showed a recently filmed reconstruction of the events surrounding the discovery of the body on August 27, 1974 by farm worker Andrew Head and the subsequent investigation at Swaffham police station.

The programme-makers spoke to the original scene-of-crime officer, Dickie Bass, Det Con Richard Dennison, who carried out house-to-house inquiries at the time, and forensics experts who did the recent re-examination of the body and discovered evidence from her pelvic bone that she “might have had a pregnancy”.

Despite a massive inquiry following the gruesome discovery the victim was never identified, her head was never found and police have no idea who her killer may be. The only details known are that the woman was aged between 23 and 30 years old and was wearing a pink Marks and Spencer nightdress. She was covered in a National Cash Registers sheet.

Det Insp Guy speaking on his way to the BBC studios and said he hoped for a strong response to the appeal, which was one of the main sections of the programme.

“The idea is that we try to attract the attention of people who knew the woman,” he said. “With any inquiry we have to establish the victim before an investigation into who committed the crime. With a national audience we hope somebody will know something. People don't just vanish. We still have a credible opportunity to resolve this case through a DNA match. Hopefully by Monday or Tuesday we will have sifted through the calls and be able to find some positive leads.”

Since the case was reopened the investigation team has already ruled out 11 women who went missing in 1974 after carrying out DNA tests on their families who came forward as a result of the new appeal. There are still a large number of potential leads they are following up.

Last night a Norfolk Constabulary spokesman said: “We would ask that anyone who was aware of a young woman going missing in 1974 to contact the MIT at Norfolk police.

“It maybe that you were told or became aware of a story that didn't sound credible at the time, such as your neighbour or friend had left the family home or run off with another man or perhaps gone back to her mother.

“It maybe that you felt this sounded odd at the time but have never reported it. If that is the case please call us on 01953 424533 and 01953 424529.”