Billie left the building through the grand stone portico and wandered down the short flight of steps into bright sunlight. It was late October and the leaves on the trees in Brunswick Square were a fluttering tessellation of reds and golds in the brisk autumn breeze. Billie pulled her scarf up higher to cover her chin and the lobes of her ears and set off in the direction of St Pancras station. She was trying to recalibrate her place in the world. She had thought that a visit to the Foundling Museum might help. But it hadn’t. The buttons, pennies and scraps of cloth left by desperate mothers as tokens by which they could identify their children, should they ever return to collect them, were heartbreaking to see. The humblest of objects, vessels for the most precious hopes, however remote they might have been. The final, fragile umbilical thread between mother and child.

Billie had no real idea what she had been looking for, but whatever it was, she hadn’t found it in Brunswick Square.