Sara hesitated, reminding herself what was their shared knowledge and what was hers alone. Patrick now knew about the five Muslim files, Sami’s story, and a deserted place with a man called ‘the Adviser’. He did not know that the files were MI5 KV2 sourced, nor the existence of Sayyid, nor Sayyid’s indication that they were the first step to revealing something cankerous within the secret state. And neither of them knew what that canker was, nor what lay further on the route towards it. Who was ‘the Adviser’? Who was the woman? Above all, why the need now to rake over these coals?

‘You’re cogitating,’ he said.

‘Yes,’ she smiled. For the moment, she would leave those pieces of knowledge where they stood. ‘I was thinking I wished I knew the answer to your question.’

He was the one who now hesitated. ‘Any suggestion – hint even – that it was more than threats and scares? That they actually did away with anyone?’

She detected an uncharacteristic anxiety – as if he’d rehearsed the question. She frowned. ‘No. Not from him. Why?’

‘Just wondering.’ He paused. ‘’Cos that would be a different level.’ As they stopped at red lights, he turned to her. ‘You OK?’

‘Yes, fine. Feels like you’re the twitchy one.’

He grinned. ‘No, not at all. Just drifting.’ The lights changed, he accelerated decisively away. ‘Would you mind something?’

‘What?’

‘It’s my boy’s football night and I always try to be there.’

‘Your boy?’

‘Yeah.’ He grinned. ‘Nathan, he just turned nine.’

‘You never said.’

‘Well, it’s not part of this, is it?’ He seemed uncertain whether to go on.

‘You can’t stop there.’

‘It’s my regular day of the week. And every other weekend.’ He went silent; she waited. ‘He lives with his mother. Well, mainly with the nanny as far as I can see.’

‘She works?’

‘When she feels like it.’ Sara saw she’d scratched a sore. ‘She went off a long time ago. No shortage of money her side.’

‘I see.’

‘You keep the car, I’ll get a taxi to Preston station. Be back on the first train in the morning. Will you be all right?’

‘Of course I’ll be all right, Patrick.’ The words came out more acerbically than intended.

His grin broadened. ‘Someone said you don’t tolerate idiotic remarks.’

‘Only when they’re made by clever people. I’ll drive you to the station. You can sit in the back if you want and I’ll wear a chauffeur’s cap.’

After dropping Patrick off, Sara felt oddly irritated by her pleasure that he had no wife in tow – but, unless she’d misread him, puzzled by that trace of anxiety. It seemed a long way to come and go for a kid’s football night.