The sea, viewed from the top of the steep valley, is a distant pool of blue decorated with a scattering of rocky islets. Here ‘my people’ (as my other half puts it) gather, unperturbed by the intense hail shower that sweeps over us. We pull on our wellies and waterproofs in the shelter of our car boots until the storm slinks away, uncovering a cleansed sky.

A few years back I hosted a Coastwise North Devon field trip to the south Cornish coast. Today I’ve been invited back for a north Cornwall foray with this dedicated group of marine naturalists. There could be no more serious band of rockpoolers. Should there be any unusual species on this shore, they are about to be discovered.

The walk down the valley to Porth Mear beach never disappoints, even in the muddy aftermath of a hail storm. Our party is accompanied by the trills of the first skylarks of summer and the first swallows dancing over the marshes.

My main objective today is to photograph the corals. Like so much of our colourful marine life, the scarlet and gold cup coral (Balanophyllia regia) is barely the size of my fingernail and prefers to live in the most awkward spots possible.

When I last found corals here, I crawled into a damp overhang on my belly, discovered the space was too small for my camera’s waterproof casing and removed it so I could hold my camera at arm’s length into the dripping cave (it died soon afterwards). The resulting photos showed blurred bloblets. The colours were lovely but beyond that you had to use your imagination. I suspect my new camera can do better.

The water is slow to run out today. A swell is building in advance of a storm and waves are rushing into the gullies that I was hoping to explore; the ones where I last saw the cup corals. Despite that, it’s one of the best tides of the year, and with so many expert eyes on the case it’s not long before a shout goes up and people gather round. 

In a shallow pool at the back of a rocky grotto are dozens of scarlet and gold cup corals, spots of colour as bright as a sunset. Each one has a central disc of fiery orange fringed in rays of saffron yellow tentacles. I can only see this by lying down and pulling myself over the rocks until my head is wedged in the overhang  so deeply that salt water dribbles down my forehead. I have a small head, small enough to wear my child’s bike helmet; just occasionally that’s useful.

This time my camera fits easily through the slit in the rocks and after a fair amount of wriggling I find a way to position it in the water and focus. A clear shot of the cup coral, translucent spotted tentacles and all, appears on my screen. I bang my head on the rock in my excitement, then take fifty more photos – just in case.

I could spend all day here, except that the spray is already breaking over my back from the waves pounding the seaward rocks. Soon the tide will swallow this gully once more. The cup corals need these fierce currents to bring them food, but I wouldn’t last two minutes in them.

We carry on our explorations, making more discoveries and enjoying the sunshine, so unexpected after the morning’s hail.

There may be places where the sea shows its treasures more willingly, where large, colourful wildlife swims all around you without having to clamber over slippery rocks, lift boulders or traipse back up a steep hill at the end of the day. But I prefer this. Just as adventure stories would be dull if the quest were over on page one, finding marine treasure would be less fulfilling if you didn’t have to work at it; or so I tell myself.

Finding and managing a decent photo of a scarlet and gold cup coral has taken me nearly forty years. Even now, I’ve only managed it thanks to having ‘my people’ around me, sharing my fascination with these creatures. I couldn’t ask for more.