I'd wanted an underground sequence for parts of my 12th century medieval fantasy, 'Dark Angels' - most accounts of fairyland in that period assumed it existed underground, in hidden caves - and I wanted my hero's experience to be authentic. No magical lights or handy phosphorescence - just a candle, and - when the candle goes out - darkness.
So I went off to Ogof Llanymynech, a Shropshire cave, and crawled in on hands and knees, accompanied by my husband and a guide from a Shropshire Mining club. Once a hundred yards or so inside, and just before the bit where you actually had to lie down and squirm, I let the others go on, switched off my helmet light and sat in the dark for a while before turning it back on and making in situ notes:
Muddy up and down crawls with sharp and extremely gritty mud. cold and damp with dripping water - breath forms clouds. lots of little white drops on the slanted rock ceiling - the knock and click and tumble of scattering rocks - low rumble of distant talk in another chamber - a low throbbing - a lost fly buzzes past, startling - you could easily get lost as it has - the distant entrance only a fuzzy patch like a tuft of grey wool - another passage - a little tuck of darkness at the side of the floor
And, heading back for the entrance -
greenish light - irregular - glitter of light on stones, the flash of water dripping - the rich green of the outside.
Notes like these are casual, immediate, and work as touchstones for the memory, reviving the experience so I can tap into it when doing the 'serious' writing. On a second trip, we did some filming, and here's the result - my new book trailer which I hope will convery some of the sinister beauty of the Shropshire landscape and legends which I tried to capture in 'Dark Angels'.