Walking along the cliff path, we see little of the sea. Every now and then a break in the tree tunnel reveals beautiful yawning blue and perfect white sand, and we want to be down there but here we are, high above, pushing onwards.

Finally, we find a break and descend through soft slippy-sanded dunes. We are the other end from Godrevy and the cliffs we stood on yesterday sit squat on the horizon. A sign warns of swimming anywhere near the estuary for the dangerous currents that lurk beneath the surface where the sea and river meet. We go instead into the water right where we descend at the base of the cliff, as far from the estuary as we can get.

It’s shallow here and we run a long way, water spraying out from ankles, then shins, finally knees, before we dip in. The depth fluctuates and swimming involves not bending your knees too much for fear of grazing them. Beneath the surface, the sand has formed hard wavy lines. We run, then dip and pull ourselves along, then sit on the sand and rock with the waves. The tide is moving fast and soon even keeping shoulders covered is difficult.

We splash instead, changed out of wet costumes and into towel ponchos, watching the water recede and leave us with its wiggly lines, it’s low puddles reflecting dropped clouds, it’s squelch and bubble as salt water vacates holes left in the sand by now invisible creatures.

The water is moving out so fast that we are able to walk past the cliff that previously marked the end of the bay, along sand that still sparkles with seawater. We sit on the rocks and wait for it to go out further so we can climb a set of steps cut out of the cliff. The water vanishes as if it’s been sucked into a sinkhole in the distance, and we sit and watch as the sand is left shining and exposed. The sea is ever changeable, ever astonishing and much, much bigger than any of us.

I’m raising money for the Alzheimer’s Society. Please sponsor me at http://www.justgiving.com/swimbonnieswim