‘Yes, you’d think that would be the explanation. But our first examination of the metadata to try to retrieve it contains no indication that such a message was sent.’

‘That’s crazy,’ said Sara. ‘I read it.’

‘So you said.’

‘There are circumstances—’ began Patrick.

‘If you could just bear to hold on a minute, Mr Duke,’ said Buttler, showing for the first time a touch of steel. ‘I’m just trying to get the facts and chronology straight. Would you object, Miss Shah, if we borrowed your phone for a few hours at your convenience to make sure the message was there? We should be able to retrieve it.’

Sara turned to Patrick. She knew she’d read the message – why else would she have returned to the office? – but had a sickening feeling of some insidious trap closing on her. ‘I told you I texted my reply to say I was coming in. That’s still there. So I could only have been replying to his text.’

‘Are you trying to imply,’ interrupted Patrick, ‘that in some way Ms Shah is inventing this text? And for some bizarre reason wrote her own text in reply just for the sake of it?’

‘No, sir, I’m implying nothing.’

‘Because if so, you may need to move on to more formal ground.’

‘At this point,’ said Buttler amicably, ‘I feel it’s best for all our sakes to continue to proceed on an informal basis.’

‘I understand,’ said Patrick, ‘that certain applications of smart phones allow a user not just to eliminate traces of sent messages from their own phone but also all traces, including metadata, from the receiver’s phone.’

‘You’re ahead of me on that one, Mr Duke. Here it’s the geeks in their funny rooms who look after all that.’ He smiled sweetly. ‘But I’ll take your word for it.’

‘I have no problem whatsoever with you inspecting my phone,’ declared Sara abruptly. Patrick glared at her. ‘I’ve nothing to hide. If a third party has intervened to delete this message from Sir Francis’s phone and, in that case I suspect, my own phone, that will require further investigation.’

‘What third party, Ms Shah?’ asked Buttler. ‘And for what motive?’

‘That is your job to establish, Mr Buttler,’ said Sara, faking her lawyerly smile.

‘Indeed,’ said Buttler, acknowledging it. ‘Moving on, you gave me the timings of your comings and goings at the Inquiry office.’

‘Yes. CCTV will confirm the exact timings if there’s any need for that.’

‘Unfortunately not,’ said Buttler. ‘CCTV appears to have been out of action last night.’

‘What?’ burst in Patrick.

‘Yes,’ he mused. ‘Ms Bailly didn’t seem too surprised. She told me it was often “on the blink” – to use her exact words.’

‘Why the hell didn’t she get it sorted?’ said Patrick.

‘She didn’t seem to view it as a priority,’ said Buttler.