Metal detecting

A metal detector transmits an electromagnetic field and listens for the response of buried metal. Modern machines can distinguish, roughly, between ferrous and non-ferrous targets and estimate depth, which lets you leave most of the iron rubbish in the ground and dig the things worth digging.

The hobby is really three: searching cultivated land for artefacts and coins, working beaches for modern losses and jewellery, and detecting at organised club digs and rallies. The first is where the archaeology is, and where the legal duties bite hardest.

It is worth being clear about what the hobby is not. It is not archaeology, and detecting on protected sites is a serious offence. But the responsible end of it — recording finds with the Portable Antiquities Scheme — has produced one of the largest archaeological datasets in Europe, built almost entirely by amateurs.

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   Step 1: Join a club before buying a machine

   Clubs give you insurance, access to permissions you could not get alone, and — most valuably — somebody experienced standing next to you for your first few hours. It also short-circuits the biggest barrier, which is finding land to search.

   You will know it worked when: You have somewhere lawful to detect and somebody to ask.

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   Step 2: Buy a mid-range machine, not the cheapest and not the best

   Around £200–£400. A very cheap detector cannot discriminate usefully; a top-end one has settings you cannot yet interpret. Choose one with a strong second-hand market so you can move on cheaply.

   You will know it worked when: A machine whose signals you can learn to read.

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   Step 3: Learn your detector in your own garden with a test bed

   Bury known objects at known depths — a coin, a ring pull, a nail, a piece of foil — and learn what each sounds like. Two hours doing this is worth twenty hours in a field guessing.

   You will know it worked when: You can tell an iron nail from a hammered silver coin by ear.

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   Step 4: Dig a clean, replaceable plug

   Cut a three-sided flap, fold it back on the hinge, retrieve the target, and replace it so the grass knits back. Landowners lose interest in the hobby entirely when their field is left with holes in it.

   You will know it worked when: Your permission survives the first visit.

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   Step 5: Record what you find and where

   Photograph the object, note the grid reference, and take it to a Finds Liaison Officer if it looks old. Most FLOs run regular finds days.

   You will know it worked when: Your finds mean something beyond your own shelf.

This is a hobby conducted almost entirely on other people’s land, and it has a reputation problem it did not entirely earn and cannot entirely shake. That shapes the culture more than anything else does: the conventions below exist because the alternative is losing access — for you, and for everybody who comes after you on the same farm.

• Written permission is convention, not law — and get it anyway — The NCMD Code requires permission before going on to any land. It does not require that permission to be in writing. Everybody sensible writes it down regardless, because farms change hands, farm managers move on, and a verbal yes from somebody who has since left is worth nothing at all on the day you are challenged.
• The finds agreement is settled first, not later — A split of anything valuable — fifty-fifty with the landowner is the usual starting point — is agreed before the first search and written down alongside the permission. Nobody enjoys that conversation and everybody who has skipped it has regretted it. Treasure has a statutory process and a reward that is shared; ordinary finds have nothing but what you agreed.
• Recording finds is the price of the hobby — The Portable Antiquities Scheme is voluntary — a partnership between the British Museum and Amgueddfa Cymru, run through more than forty locally based Finds Liaison Officers — and the community treats recording as obligatory anyway. It is also a condition of most agri-environment agreements, so on a great deal of farmland it is contractually required of the landowner whether or not anybody mentions it to you. A detectorist who records is contributing to archaeology; one who does not is emptying a filing cabinet.
• Fill your holes, and be seen to — The most consequential thing you will do all day. A pasture with holes in it is a vet bill and a lost permission. Cut a neat flap, put it back, tread it down, leave nothing.
• Discretion about locations is a norm, not secrecy for its own sake — Detectorists are vague about where a good field is, and it reads as cliquey until you understand what it protects. Nighthawking — detecting without permission, usually at night, usually on known sites — is theft and criminal damage, and a productive field named in public is a field that gets visited. The information moves privately, to the landowner and the Finds Liaison Officer, because those are the people who can do something with it.
• Clubs hold the permissions — The realistic route in for most people. A club has fields, relationships with the farmers, and members who will teach you to read a signal — and in exchange it expects the code to be kept, because its permissions depend on that. Rallies are the other route and a different experience: a hundred people on one farm for a weekend, with the finds process run by the organisers.

The tone of the hobby has changed markedly in twenty years and you will meet both halves of it. There is a long and genuine antagonism between detecting and professional archaeology. There is also a large and growing group of detectorists who record everything, work with their Finds Liaison Officer, and have between them redrawn the distribution map of Roman and medieval England more thoroughly than any excavation programme. Which of those two hobbies you have joined is decided entirely by what you do with what you find.

• The detector — VLF machines are the standard for land: they discriminate well between metal types and are efficient on most soil. Pulse induction machines ignore ground mineralisation and salt, which makes them the choice for wet sand beaches, but they discriminate poorly and you will dig everything.
• A pinpointer — A short-range handheld probe used inside the hole once the main coil has found the general area. It turns a ten-minute dig into a two-minute one and dramatically reduces damage to both the find and the ground. Buy one immediately.
• A digging tool — A proper detecting trowel or spade with a serrated edge. On pasture, a purpose-made plug cutter. A garden trowel bends and makes a mess.
• Headphones — Not a luxury. They reveal the faint, deep signals that a speaker in wind loses entirely, which is most of the interesting targets.
• A finds pouch and a rubbish pouch — Two separate ones. Everything ferrous and modern that you dig comes off the field with you — this is both good practice and the reason landowners renew permissions.

• Field and pasture detecting — Searching cultivated or grazed land with the landowner’s written permission. The mainstream of British detecting, the branch the recording obligations were written around, and where nearly all significant finds come from.
• Beach detecting — Saltwater beaches, with a machine that can handle wet sand. Legally the simplest branch because much of the foreshore is accessible under permissions that fields never are, and mechanically the hardest on equipment.
• Water and underwater — Shallow water, rivers and diving, with waterproof machines. A specialist branch with its own equipment and its own permissions, and one where the safety considerations are the water’s rather than the hobby’s.
• Relic and battlefield — Searching sites of known historical activity. The branch where scheduled-monument law and the recording obligations matter most, and where the difference between detecting and damaging a site is the whole question.
• Urban and park detecting — Parks, commons and verges, almost always requiring the local authority’s permission and frequently refused. Convenient, low-yield, and the branch most likely to end in a conversation with somebody official.
• Prospecting — Searching for gold and mineral rather than for artefacts, in the few British areas where it is viable. Different machines, different licensing, and a different community.
• Magnet fishing — Not detecting at all, constantly confused with it, and carrying a real hazard the rest of the hobby does not — ordnance is recovered from British waterways every year. Named here so the boundary is visible.

Detecting has a steep first year and a very long tail. Most beginners stop because they cannot get permission and are bored of ring pulls, and almost everything that separates a beginner from somebody finding interesting material is about land and research rather than about the machine.

• Learn the machine on ground you know — The first hundred hours should be about learning what your detector sounds like over different targets at different depths, and the fastest way is to bury known objects and dig them. Everything after this depends on being able to trust the signal, and it is the step people skip in order to get on to a field.
• Getting permission, which is the real bottleneck — Land access is the whole hobby. Almost all productive ground is private and permission is a relationship rather than a transaction: being insured, being able to say what you will do about holes and litter, and writing down what happens to anything found is what turns a conversation into a yes. Most detectorists get their first permission through somebody who already has one.
• Research before you walk — The difference between a field and a good field is almost always documentary. Old maps, tithe and enclosure records, place names, footpath alignments and aerial photography all narrow it down, and this is the part of the hobby that keeps people interested through a bad winter.
• Recording finds, and why it is the point — A find with no record of where it came from has lost most of what made it interesting. The national recording schemes exist to capture that, they welcome ordinary finders, and reporting is what distinguishes the hobby from the thing it is accused of being. The law section on this page covers what must be reported as opposed to what should be.
• Joining a club, and going to rallies — A club is where permissions, machine knowledge and identification all circulate, and where somebody experienced will tell you what you have actually found. Organised rallies give access to land nobody could get individually, and they are also where poor practice is most visible, so they are a good place to work out what standard you want to hold.
• Identification and conservation as skills of their own — Cleaning is where more finds are destroyed than by any spade. The general position is to do as little as possible and to ask before doing anything to a corroded object, because patina and surface detail carry the information and neither comes back. Learning to identify what you have — by fabric, form and period rather than by guesswork — is a long, genuinely absorbing study.
• Specialising by ground or by period — Beach and salt-water detecting, ploughsoil archaeology, and searching for a specific period all want different machines, different settings and different research. Choosing one is how people stop buying detectors and start finding things.