Now that she’s started sea swimming herself, she notices women like her everywhere. She’s discovered The Salty Seabirds, an offspring of a social enterprise set up by two women to help people with their mental health. She was surprised to learn that there’s thousands of members on the Facebook group and she joined up herself, reading the helpful tips on swimming in cold water. It feels exciting to be part of such a big community, but she likes being part of the Sea-Gals group the best.

Today, Dominica has reposted a picture of a swimmer in a Wonder Woman cape from another sea swimmers’ group, the Blue Tits. It’s been so long since she’s been away anywhere that Claire feels a little thrill at being connected to these women on the other side of the country.

She studies the picture – a group of women larking around on the shore; women in costumes with wobbly bottoms just like hers, their gloved hands held aloft, grins on their faces. It’s comforting to know that her tiny gang on the beach is part of a vast movement of swimmers. When everyone else is moaning half the time, the fact that there are people enjoying the benefits of cold water feels like a massive force for good. She likes to think of this veritable army around the coastline of Britain as hardy, can-do types who get things done. Because that’s the gist of the post. That swimming in cold water invokes one’s inner superhero.

Claire has never thought of it like that, but it’s true. Not believing in a million years that you might be able to go in, and then actually doing it is powerful stuff. You may find, the quote says, that your superhero power stays with you through the rest of your day. You might find the courage to wear a brighter colour or say something daring at a meeting.

She can see that Dominica is typing and she clicks the message. She’s asking if anyone is around now for a swim at low tide. Claire feels a leap of excitement. She looks at the clock on the cooker. She can do it. She can get down there and back before she really has to chivvy the boys along with their schoolwork. Pim doesn’t notice as she leaves.

The tide is going out and there’s a sea mist making everything slightly blurry when Claire joins Helga and Dominica on the beach.

‘They must know something we don’t know,’ Claire says, as she puts her bag down. The surfers, clad in black, are floating on the still water by the burnt-out pier. There’s not even the hint of a wave. What are they doing?

Tor comes down from the prom to join them, her feet sliding in the slope of pebbles. Apart from their gang and the surfers in the distance, there’s nobody around, except for the man she can see stretching on the bandstand next to a tent. Not a very relaxing place to pitch up, she shouldn’t imagine.