The code, which was agreed between groups representing archaeologists, metal detectorists and landowners, was announced last month. It gives a clear definition of good practice before, during and after metal detecting.

Steve Critchley, the chairman of the National Council for Metal-Detecting (NCMD), described the code as both fair and practical. He said the code had been two years in the making and was a result of an informed debate.

'By adhering to this code, the vast majority of metal-detectorists will be able to demonstrate that they have a genuine interest in the past and wish to benefit from the knowledge they gain from their hobby.'

He said he hoped the code would overcome some of the prejudice that metal detectorists had faced in the past. Sticking to the code will now be a condition of membership for the NCMD.

Mike Heyworth, the director of the Council for British Archaeology, said the code was a major step forward. 'It emphasises the positive contribution that metal detectorists can make to the study of the past,' he said. He added that it also made a distinction between the majority of responsible detectorists and a 'minority of irresponsible individuals who use their equipment for personal gain'.

Caroline McDonald, a finds liaison officer for the Portable Antiquities Scheme (PAS) in Essex, welcomed the code and said she hoped it would enable some of the animosity between detectorists and archaeologists to be put aside.

McDonald said there had been an improvement in relations between the two groups since the advent of the PAS, but that she still receives a mixed reception when she goes to some metal detecting clubs.

However, there is another threat to Britain's archaeological heritage on the horizon. Finds liaison officers have become aware of groups of detectorists from abroad taking finds out of the country without applying for export licences. At the end of last year, there were two seizures of finds by customs involving such groups.

Roger Bland, the head of the PAS, said he hoped the seizures would be a deterrent and added that the PAS had organised a meeting with customs and excise to discuss the problem. 'It was very difficult a few years ago to get customs to take any interest, but the issue is now moving up their agenda.'

Sharon Heal