OUT IN the orderly fields of Bedfordshire a battle is taking place between a grave-robber with a lust for ancient loot and a woman who is doing her best to preserve the bones of history. The conflict has involved night raids, tip-offs, traps, arrests and secret photographs of a crime apparently in progress. But no one has been charged, and no one has been brought to court. So the man who plunders archaeological sites by night, making off with irreplaceable pieces of history, must be referred to only as Charlie, though it is known who he is, and that is certainly not his name.

The woman is Evelyn Baker. As assistant principal archaeology officer at Bedfordshire County Council, it is her job to oversee the sites targeted by Charlie and try to beat him off. She is losing. Charlie has struck many times over the past two years, and the continuing battle has become a symbol for much that is wrong with current heritage law and its enforcement.

The tale began in 1990, when field workers were first called to a vast archaeological site west of Bedford that was about to be sliced by work to lay a new sewage pipe. This is how much archaeological work is done nowadays: a developer or utility plans a job which cuts through something interesting, so money is handed over for exploration before the JCBs roll in.

Anglian Water did what it could to avoid damaging the site of a Roman villa and ancient cemeteries, then paid for excavating what remained. Evelyn Baker's team leapt to their trowels.

Two things happened. First, archaeologists who dug experimental trenches became excited by what they found: 'There was important evidence of continuity from the Roman to Saxon period,' says Mrs Baker. A grave - fifth century, containing a skeleton with a beautiful comb around its neck - was among initial discoveries. Second, a series of sinister little trowel holes began to appear in the area around the test trenches - the sort left by a man with a metal detector, burrowing to the source of a clear signal. Mrs Baker had a sinking feeling.

A word about the law. Unless they are made of gold or silver - in which case a coroner's court decides ownership - archaeological artefacts belong to the owner of the land where they are discovered. Archaeologists say this is crazy, because it means no one need ever report a find. They are campaigning for new legislation.

In 1991, therefore, when excavation work began in earnest at the Bedford site, Mrs Baker contacted the two landowners involved - the Church of England and a private company - and asked that only archaeologists from her team should be permitted to use metal detectors there. Letters of agreement were swiftly returned, but proved ineffectual. As the site was stripped of topsoil for detailed examination, the night raids began.

'There was one morning,' says Michael Dawson, in charge of digging, 'when we arrived to find 40 holes across the site.' The cruel truth about raids of this kind is that it is impossible to know what is being stolen. It could be coins - which help to date a period - or exquisite jewellery. However, it is probably worth something, or no one would bother to come back. And they did. Time after time.

Mrs Baker guesses that up to 15 people using metal detectors - 'metal detectorists', she calls them - had a stab at the site, but one face, and one name, stood out as the most persistent and most brazen. This was Charlie.

How did she know? Because he was seen - and photographed on site with a metal detector - and asked what he was doing. Mr Dawson says: 'I took the photo. He was plausibility itself. He was going to make some money to go to America. He was not specific about what he had taken and the things he had with him then were just pieces of lead. He did say he had taken stuff from that site.'

So Mrs Baker contacted the police, and in April 1991 Charlie was caught on site and arrested, together with another man. He had at least one Roman coin on him, and Mrs Baker says, 'We thought, 'We've got him'.'

She was wrong. 'In January 1992 I had a visit from a police constable who was upset,' she recalls. 'He said the Crown Prosecution Service was not going to prosecute because there was not a 51 per cent probability of success. Also, the site was not ringed with notices saying this was an archaeological site and that theft would lead to prosecution. That is nonsense. Why not put up floodlights for them as well?'

Digging was halted for several months while contractors laid the pipeline, but autumn brought stage two of the excavation, and the problems began again.

'Mike was being driven spare,' says Mrs Baker. 'We had 92 skeletons on site, and night after night he would find that archaeology from them was being interfered with.'

However, in October 1992 there was a breakthrough. Mrs Baker received an anonymous call naming Charlie, and saying that he planned a raid that same night. A guard with a portable telephone was posted, and when men were seen moving in the darkness, police were called.

Charlie and another man were arrested in possession of torches and spades. 'They were let off,' says Mrs. Baker. 'I was told by the police later that it was largely because of the previous situation, where they were caught on site but the police couldn't get it through the CPS.'

At this stage, two new pinpricks were added to the pain of frustration. A supervisor at the excavation reported in November 1992 that a man he recognised as Charlie approached him on site and began boasting. The supervisor's report says: 'He proceeded by openly admitting to me that he, along with several colleagues, had detected on the present site on several occasions . . . The activities were mainly carried out in the evening. He spoke of retrieving a number of coins and other objects (number not stated) but finding enough for him to make some money out of the exercise. As well as telling me about his detectorist activities on the present site, he brazenly told me about some of the objects he had dug up on the 1991 excavation. Some of these objects, he told me, were taken across to America and sold for quite a considerable sum.'

Next, a local newspaper interviewed Charlie, named him, and claimed he had boasted to the reporter '. . . of desecrating graves and stealing ancient coins and jewellery'.

But the raids continued. In April this year, a new project was started a few miles away from the completed Bedford dig, at a Roman farm near Sandy. A man claiming to be a sixth- former rang county council officials and asked for details of the site, saying he was interested in taking photographs. They happily gave them.

'Over the eight weeks we were there,' says Michael Dawson, 'a hundred holes appeared. This site has been under excavation, on and off, since 1987 and we have never had metal detector trouble before.'

Mrs Baker says: 'Security was greatly escalated. It became quite a game.' Someone removed the steps from the security guard's Portakabin and he fell over. Someone wrote a message on archaeologically cleaned surfaces: 'Aslep (sic) on the job. . .', followed by two obscenities. Mrs Baker says a message with the same mis-spelling was carved into the Bedford site a year before.

And there it rests. Both digs are over now and nobody knows what has been stolen. But at the very end, low- grade metal artefacts were being left behind, presumably in favour of better things that have just never been seen or recorded.

What is the result? Mrs Baker says her department has changed its work methods - to shorter periods. They spend more on security. They believe they have blanks in their historical knowledge. They are worried about revealing plans for new digs, but remain 'determined' to continue doing so. They are concerned about their relations with metal detector users, the majority of whom are supportive and genuinely care for the heritage they help to uncover.

Mrs Baker is angry. She says: 'It seems monstrous that this man is allowed to do the same thing time after time and feel he is immune to any form of prosecution.' The police will only say that 'a matter has been dealt with, a decision taken some time ago, and the matter discontinued'.

Richard Morris, director of the Council for British Archaeology, says that similar night-raids take place regularly in other parts of the country, particularly in East Anglia: 'They can do a hell of a lot of damage.'

A campaign is under way to change the law so that all archaeological finds must be reported - which would be useful, but would not deter hardened raiders such as Charlie. There are plans by Surrey Archaeological Society, together with Lord Perth, to promote private legislation that would - among other things - criminalise trespass with intent to treasure hunt. But the future of such private legislation is by no means certain.

Meanwhile, in the fields of Bedfordshire is a man who wants to get at history before anyone else does, who seems to be very good at it and who tramples over precious messages from the past to make a buck.

I spoke to Charlie before writing this and asked for a comment, but he demanded pounds 200 and, when I wouldn't pay, he shut up.

(Photograph omitted)