The approaching shoreline is an arresting one. A few yards up the cream-coloured beach it’s England – well-kept hedgerows, chalk-dust paths, everything with that tamed look so welcoming to Anglophiles. Except this is the Atlantic. All around, the UK continental shelf is having one last fling with the open air – a scatter of low granite islands, nibbled inwards with half-circles of white beach as if the place was drafted with a pair of compasses. There’s so much sky it gives me a kind of reverse vertigo…

But I’m not looking upwards. I’m looking down.

When can we go swimming, Dad?

The boat carves its way through the glassy green water. It’s actually, actually green. The sun’s baking down, laying on my shoulders like a hot towel but when I trail my hand down the side of the boat I can feel the coolness of the air above the water. I flex my fingers, enjoying the play of cold air through them, and then drop them into the sea. It’s like reaching into an icy jewel – the dazzling reflection of the sun scattering into luminous, oily curls of jade and emerald.

I really want to go for a swim. When can I?

We round one of Tresco‘s headlands. I can see everything on the sea floor – pebbles, sand rippled like a ploughed field, fish flicking about so fast you blink, thinking it’s something on your eyeball. This is the colour of the sea when you’re on holiday. This is exactly that colour. But it also stirs my fragments of childhood memories from Cyprus. I can taste a snorkel, smell a rock-pool. I know how delicious that water is.

WHEN can I GO for a SWIM, DAD? Mum, tell Dad we need to go SWIMMING!

It turns out that visiting the gardens at Tresco is my Mum’s idea – and we don’t have time to go swimming. Anyway, it’d be cold and I’d have got really wet, my mum tells me when we’re back in Yorkshire with the rain coming down hard. Thirty years later, I know she half-lied. The Isles of Scilly enjoy the balmiest temperature ranges in the UK (which explains the palm trees dotted around). It’s hardly tropical, but it’s the best you get in this country…

So when can I go for a swim, Mike?

Soon, Mike. Soon.

Image: sunny_me, Tom Corser (www.tomcorser.com).