Detectives investigating the theft of Lord Nelson artefacts worth more than �36,000 from Norwich Castle Museum say a high profile television appeal has helped generate new leads.

Millions of television viewers saw the appeal on the BBC's Crimewatch programme on Tuesday night in an attempt to solve the crime which was discovered on February 25 by an off-duty police officer who was visiting the museum.

Investigating officer Detective Constable Jon Gouldson said: 'I'm hopeful that as a result of such high profile coverage on Crimewatch we will be able to resolve this case.

'We have received some positive feedback from the public with half a dozen calls received last night as a consequence of the appeal. These calls have generated some fresh leads that we will be following up in due course and that we hope will contribute to locating the offenders and the recovery of the stolen items.'

Items stolen from one of the museum's cabinets included a �25,000 mourning ring and a �10,000 saucer, above.

Police have been scouring CCTV images from the castle, but with so many images to trawl through, they have yet to identify a suspect.

The stolen saucer is from an 1802 tea service, which was part of the inventory at the home of Norfolk's naval hero.

The stolen ring, which dates between 1803 and 1806, is enamelled and bears the letters N and B. It was in a box dated 1805.

Two bronze medals, worth �400 each, were also taken. One commemorates the Battle of the Nile on August 1, 1798, while the other marks the death of Lord Nelson and is dated 1805.

A stolen gilt metal box containing four medallions commemorating the victories of various admirals has been collectively valued at �1,000.

The theft was discovered a few days after museum staff foiled an attempt to steal a rhino horn.

Four people, at least two of whom paid to enter the castle, broke into a case and took the heavy head out of the gallery before being disturbed by a curator who grabbed back the rhino head.

The raiders, all described as wearing dark coloured clothing, are believed to have left in a dark hatchback vehicle parked outside which was driven by a fifth person.

The attempted theft, at about 1pm on Monday, February 20, followed a theft from Ipswich Museum where a rhino horn was stolen, while raids have also happened at museums in Europe including ones in Florence and Brussels.

Rhino horn is prized in Chinese medicine for its alleged aphrodisiac qualities – and said to be twice as valuable as gold.

The crimes sparked an internal review of security at the museum, with the national security advisor for the Arts Council also agreeing to carry out a full security review.

The Crimewatch programme has been screening crime appeals for more than 25 years and pulls in four to five million viewers each month.

Anyone with information about the theft of the Nelson artefacts, or about the attempted theft of the rhino horn a few days before should call Norfolk police on 101 or Crimestoppers on 0800 555111.