‘It may not be money. A political hostage taker might seek a subtle change in policy, the removal of a clause in a piece of legislation, even the approval of a citizenship request. Or the barring of one. We’ve all read about the strength of the far right in Germany.’

Ulbricht had clearly not considered all of these possibilities. ‘I will think about this.’

‘I don’t want to alarm you,’ Gillard said. ‘It’s entirely possible that your daughter has had some kind of breakdown and does not want to be near anybody at the moment. But it’s very important that if someone has abducted her, you must scour not only your own official and private emails, landlines and mobiles, but ask your family and close friends. A ransom demand could come by post, it could be spray-painted on your garage, it could be placed as a coded advertisement in a newspaper.’

The minister nodded, clearly impressed by the detective’s lateral thinking. He consulted the mobile phone which had sat with discreet silence throughout the meeting. ‘Ah, my time has evaporated. I have to catch a flight to Brussels for a conference on refugees. So many of them have daughters too, in as great a danger as my own, if not more. And I haven’t finished writing my speech.’ His briefly raised eyebrows spoke volumes. ‘I will have my meeting with the Home Secretary during the flight.’

‘Do you have just one minute for me to show you the footage of Beatrice?’ Gillard asked.

He hesitated for a moment, but then said, ‘I’m told my officials are waiting outside. Please email it to me.’ He dropped a business card on the desk as he stood, his shoulders groaning under the weight of responsibility. Gillard stood too, and they shook hands firmly and with feeling.

‘I will do everything I can,’ the detective said, passing across his own business card. ‘Ring me, any time.’

The minister nodded. ‘She is our only child. Precious beyond dreams. Our world dangles by a thread.’

Spurred by the exhibition of guilt and shame, Gillard texted his own long-suffering wife, Sam, to tell her that he would not be in until eight or nine o’clock. He had only just finished when the young female PC who had summoned him earlier arrived with a laden silver tea tray, of all things.

‘Where’s he gone?’ she asked.

‘To Brussels on the plane.’ The tray contained two expensive bought-in designer coffees and an entire box of artisan biscuits.

‘Oh shit, I’ve just driven in to get them from the deli in the centre of Guildford.’

‘They won’t be wasted. Take a seat.’

‘Where’s Her Royal Highness?’ she said, looking around as if Alison Rigby could be lurking around any corner. ‘She told me to get them and give her the bill.’

‘Schmoozing with the Home Secretary if she’s got any sense,’ Gillard said. ‘She’ll have her hand out for budget. So have a biscuit with me. Take a moment’s peace, because you never know when the next one will be.’