‘No need,’ he replied, starting to walk away. ‘It’s a lovely evening.’

Bennett watched him turn out of Neville Street, then she rushed back inside number nine and up to her room. She grabbed a jumper and the small packet of crackers she kept on the mantelpiece over the fireplace, then ran back out into the street.

White’s Anglia was exactly where he said it would be, and half an hour later she pulled into Methley Street, a quiet row of small but well-kept terraces just north of the Oval cricket ground in Kennington.

Chapter 57

Chapter 57

Valera had spent the night alone. After Peterson had persuaded her to eat the tasteless sandwiches from the fridge, he’d explained that MI5 owned the building she’d had woken up trapped in. He confirmed what Valera already suspected: the whole of the upstairs was sound-proofed, the windows were reinforced, and the only way in or out was through the bulletproof door at the bottom of the staircase.

After she’d finished eating Peterson had asked her to tell him exactly what she was bringing to her side of their new business partnership. She spent ten minutes explaining the intricacies of spread-spectrum broadcasting, frequency degradation and code-division modulation until she realised he had no idea what she was talking about. So instead of trying to give him a crash course in advanced radio wave physics, she resorted to an analogy.

‘If you are in a room full of people talking,’ she said, ‘how do you make yourself heard?’

‘Shout over everyone else,’ Peterson replied.

‘But what if everyone else starts to shout as well?’

‘Wait for them to stop.’

‘Good. You’ve just described broadcasting at different pitches or sequences. There is also a third option.’

Peterson thought for a moment, then said, ‘Different languages.’

Valera smiled. ‘Excellent. Pitch, sequence, and frequency. If I was speaking Russian in a room full of people speaking English, another Russian person would be able to make out my voice and know what I was saying.’

‘And no one else could.’

‘Unless they also understood Russian, or were paying my Russian friend to tell them what they heard,’ she replied. ‘Now, imagine if this room we were in was very large, large enough to contain everyone in the world. Another Russian speaker nearby might hear me, but not one thousands of kilometres away or on the other side of the planet. What can I do to make sure that person can hear me?’

This time Peterson couldn’t think of an answer.

‘I build another room,’ Valera said. ‘One that only I have access to, but that has doors that open up all around the world.’