Then he was on me, breathing hard and snuffling for the chicken treats I held in my fists. I fed him the treats, his nose a wet button in my palm, and I kept hold of his harness until Scout gave me the signal.

And he flew back to her side.

Hampstead Heath was dog heaven. Dogs of all sizes passed through this meadow on their walks, some of them coming over to give Stan an investigative sniff, others lost in their own world of smells, uninterested in the little red squirt off lead for the first time.

Dogs paced along the perimeter of the meadow where the trees began, noses pressed to the ground on the trail of some long-gone rabbit or fox. But Scout and I stayed on the meadow with Stan running between us, until he was gasping with exhaustion and our bags of chicken treats were almost empty.

We were both grinning with happy relief. Stan had gone off lead and he hadn’t been lost. I took out his dog lead. It was time to go home.

And then he saw the birds.

Two fat crows, pecking the ground just beyond the tree line, and they took flight as Stan hurtled towards them. Scout and I chased after him, calling his name, but the birds had touched some ancient nerve and suddenly he was not interested in chicken treats or us.

The elm trees were old and huge on that part of the Heath, and their spreading boughs formed a thick canopy that made it impossible for the birds to take to the sky. So they flew low, flapping wildly, unable to break free.

And Stan went after them.

Within seconds we had lost sight of him. We staggered among the trees, calling his name, and within minutes we too had completely lost our bearings. The Heath was dense and wild up here, although we could hear the distant buzz of traffic on Hampstead Lane and could easily imagine our dog under their wheels. Scout began to cry. Silently, hopelessly. I put my arm around her and called Stan’s name again, though it felt useless. The traffic was closer now. There was a tight knot of fear and grief in my stomach.

And then we saw them.

The woman coming through the trees with a little red dog in her arms and another dog scampering off lead by her side. A Pekingese-Chihuahua cross. I recognised the dog before I recognised Natasha Buck in her flat cap, green Hunter boots and black waterproofs, a city girl dressed for the country.

Scout and I choked out our thanks for Stan’s safe return.

‘Don’t thank me,’ she said. She pointed at the Pekingese-Chihuahua cross daintily snacking on rabbit droppings by her boots. ‘Thank Susan.’

We thanked Susan.