‘I’m very sorry about it all,’ said Sanjit, coming out of the living room. ‘Bit of a bloody mess, isn’t it?’ He caught sight of Matty. ‘I mean, not a bloody mess, I’m sure it’s not that.’

Matty hid the card between two flat hands, as if praying. ‘Did Dad go to the Ponds? That day?’

Sanjit blinked. ‘He said he was going, yes, mate,’ he said, as if it had been quite normal. ‘He liked a swim.’ Another blink, horrified. ‘Likes a swim.’

The police station was a big red-brick building on Finchley Road, with a hairdresser’s and a Chinese herbal medicine shop next door. A Union Jack flag hung down from a pole over two old-fashioned lanterns.

The policewoman who had come to the house was there in her thick black skirt that pointed outwards. ‘Hello, love.’ She looked across the foyer. ‘Your mum not with you?’

Matty was led down a brown-carpeted corridor with plasticky windows and into a room with five desks, all piled high with paper. A man in a beige blazer leant back on his chair legs to glance over, uninterested, before tipping back down and sighing at his typewriter.

The policewoman was shuffling out digestive biscuits from a packet onto a plate. They slid off onto the table and she had to put them back on. ‘So is there something you want to tell me about your dad?’ she said, breaking off a piece of biscuit. ‘Something you couldn’t tell me before?’

‘Um. No. I just wondered if you could dredge the pond. The Men’s Pond on Hampstead Heath.’

She spoke through a mouthful of biscuit. ‘That costs money, love. The lifeguards are sure nothing happened there. They would have seen something. It was just one line of inquiry.’ She frowned at Matty. ‘He definitely didn’t take anything from the house that morning? Or say anything to you?’

‘Go get ’em, Scout,’ he’d said. ‘Enjoy your last day.’ His fingers in a gun-shape, kissing the top of them, firing gently.

‘No.’

She slotted her fingers together. Today her lipstick was the colour of water-wings, and it was straying in tiny paths from her upper lip. ‘I’m sorry about your dad, love.’ She looked down at her desk, as if she had other things to do. Picked up a pen. ‘Sometimes they go. Sometimes they come back. Believe me, I know.’ She fiddled with the gold band on her finger and said something under her breath.

Then do something. Find him. ‘So …’ Matty looked at the floor. ‘You don’t think he’s dead?’

‘Well, without – sorry, love – but without a body, no. People go missing. Sometimes it’s because they don’t want to be found.’ She pushed the plate over. ‘Have a biscuit.’

***

In warm water the body’s need for oxygen increases.