‘Just wait here,’ Kate instructed Callum, as she and Julie got out. ‘We’ll have to play tag,’ she told Julie. ‘I want her to know it’s only the two of us, so don’t make any effort to hide yourself. I’ll go first.’

Clutching her bag to her right shoulder, Natasha’s progress was hurried, broken, radiating nervousness. She’d thrown a pink cardigan over her tennis whites, but still stood out from the crowd. Kate wondered if they were being set up, but decided it was too late to turn back now.

The Russian swung into Çadircilar Street and strode through a profusion of stalls selling jeans, T-shirts and mountains of fake handbags, watches and designer apparel of every possible kind. Kate had to take an age selecting a denim jacket for her daughter as she waited for Natasha to emerge from the book bazaar opposite.

Julie brushed past her. ‘Should we go in?’

‘No.’

Natasha reappeared and hurried off, with Julie now taking the lead in her pursuit. They plunged through the Beyazıt Kampüsü Gate, past the moneychanger owned and run by SIS’s Istanbul station chief, where Kate had tried to boost Lena’s flagging courage before sending her to her doom.

It was a moment before Kate realized Julie had stopped to browse at one of the jewellery stores so she could take over again. She pulled herself together and strode on through the thronged alleyways. Her white and pink target wove nimbly through the tourists and shopkeepers trying to lure her into their dens.

A young man sidled up alongside her. ‘Can I offer you something you don’t need?’ He had sallow features, a drooping moustache, much too old for his years, and a lopsided grin.

‘Nice try,’ Kate said.

‘It has a proven track record,’ he said.

‘Not today, my friend.’

‘But life is for living today, is it not? And I have something that would look peerless on that delectable wrist.’

Perhaps she was getting rusty, or blunted by the emotional burden of Lena’s memory, but Kate was off the pace and suddenly afraid she’d lost Natasha. She brushed the man away and stopped at a crossroads, scanning the alleys around her, the excited hubbub of the crowds bouncing off the beautiful mosaic domes. She’d reached the central section of the bazaar now, where the stores were loaded with copperware of all shapes and sizes, and bashed into a young man hurrying along with a delicately balanced tray of coffee and apple tea.

She was recoiling from his curses when she felt Julie’s reassuring presence at her elbow. ‘Easy, Kate. She turned right ahead.’

Julie took the lead again and Kate breathed a sigh of relief as they hurried on. They watched Natasha browse in a silver store and, later, in booths selling inlaid boxes and painted glass. Julie let Kate catch up with her. ‘My God, we look like bloody amateur hour. Why don’t we just go and talk to her?’

‘We need to wait until we’re sure she’s comfortable.’