Start with the version you already have

Every investigation begins with a story, and the version you already hold is evidence in itself. Before you go anywhere near a catalogue, write down the tale exactly as you first heard it — the words, the place names, the odd details that seem to make no sense. Note who told you, roughly when, and where they heard it. Those small annotations will turn out to be surprisingly useful later, when you find that two tellings of the same legend differ over a name, a date or the fate of a particular character.

It helps to note the shape of the story too. Does it involve a buried treasure, a ghostly procession, a drowned village, a witch's curse, a boundary dispute dressed up as a fairy tale? Folklore tends to cluster around a handful of recurring forms, and knowing which one you are dealing with tells you where to search next.

Make the local studies library your first call

Almost every county and many large towns keep a local studies collection, usually shelved separately from the general lending stock and staffed by someone who knows it intimately. These collections gather parish histories, guides, pamphlets, old photographs, sale catalogues, family papers and the published folklore of the area — the very material that never makes it into national libraries.

Ask the staff for a few things in particular:

• Any printed collections of local folklore, legends or dialect tales.
• Bound runs of local newspapers, or the indexes that point into them.
• Parish histories and the county volume of the national historical survey of England.
• Subject files or vertical files kept on particular villages, families or landmarks.

Search the catalogue for the name of the place plus words like legend, tradition, custom and reminiscences. Older catalogues often hide their treasures behind inconsistent spellings, so try variants of the village name as well.

Dig into the county record office

Record offices hold the raw material of local life: parish registers, wills, estate maps, enclosure awards, tithe apportionments, school log books, poor law records and the private correspondence of gentry families. You will rarely find a legend written down as such, but you will often find the human situation that gave it a home — a disputed boundary, a suspicious death, a mine that flooded, a house that changed hands under a cloud.

Before visiting, check the office's online catalogue and note the reference numbers you want. Order documents in advance where you can, take pencils rather than pens, and be prepared for a very slow afternoon that suddenly produces one perfect sentence. Photograph or transcribe anything you rely on, and record the full reference: collection name, document number and folio.

Read the landscape and the maps

Legends are anchored to ground, and the ground will often explain them. Compare historic maps with a modern survey — tithe maps, enclosure plans and the earliest large-scale Ordnance Survey sheets are especially revealing. Look for lost names: a field called Gallows Piece, a lane marked Dead Woman's Hill, a pond that has since been filled in.

Place names are miniature histories. Elements meaning ford, barrow, well, cross or hollow can point to a feature that has vanished from view but not from memory. Your historic environment record, kept by the county, lists archaeological sites and find spots; it is a quick way to test whether the mound in your story is a real burial chamber or simply a convenient landmark.

Collect living memory with care

Oral history is where local legends stay alive, and it deserves to be treated as seriously as any document. Approach people through parish councils, history societies, care homes, churches, pubs and community groups. Explain what you are doing, why, and what will happen to the recording afterwards.

A few practical habits make all the difference:

• Ask permission before recording, and note the date, the speaker's full name and their connection to the place.
• Let silences sit. The best detail often arrives after a pause.
• Ask open questions: "What did people say about that house?" rather than "Was it haunted?"
• Take a note of the stories people dismiss as "just old nonsense" — those are frequently the oldest layer.

Consider depositing copies of your recordings with the local archive or oral history project, with the speaker's consent. That way your work becomes somebody else's source.

Weigh the evidence and write it down

Once you have a pile of material, sort it. Which parts of the legend appear in the earliest written source, and which creep in later? Does a Victorian antiquarian record the story, or only a twentieth-century retelling? Antiquarians were enthusiastic but not always careful, and a single imaginative nineteenth-century clergyman has seeded many a modern legend.

Be honest about gaps. "The earliest reference I have found dates from 1841, though the story claims to describe an event in the 1630s" is a far stronger sentence than a confident guess. Keep a simple list of sources with dates so readers — and future researchers — can follow your trail.

Finally, write it up while the voices are still fresh in your ear. Set the story down plainly, then add what you discovered: the map, the document, the contradictory account. A local legend well researched is not a debunked tale but a deeper one, and the telling of it is how the tradition carries on.