They were still discussing possibilities in the meeting room when a young female PC came in to tell them that Gillard was urgently required back in the incident room. ‘The German minister is here, sir.’

Gillard looked at his watch. It was only just after five. He hadn’t expected him until six. DI Duffy smirked and said: ‘Very punctual, the Germans.’

‘His daughter is missing!’ Claire retorted. ‘No wonder he’s here early. If it was one of my kids I’d set up camp in the car park, and not shift until she was found. He’s probably beside himself with worry.’

‘Fair point,’ Duffy said, hands raised in mock surrender.

Gillard and Claire Mulholland made their way to the incident room. There was clearly something important going on inside, because an enormous personal protection officer was posted outside, identified by his lanyard as being from the Bundesministerium der Justiz und für Verbraucherschutz. Another PPO was inside the room. Through the glass door the chief constable could be seen conducting a guided tour for a tall and rather imposing silver-haired man in a grey suit and red tie, and two officials that he guessed were from the Home Office. Rigby was pointing out the whiteboards where pictures of his daughter were pinned by magnets, and the detail of the train journey to Waterloo were noted in marker pen. Rigby turned round as Gillard opened the door, and introduced him to Karl-Otto Ulbricht, finishing with: ‘DCI Gillard is one of our most experienced detectives, and I have faith in him.’ She then turned to Craig: ‘I’ve already told Herr Ulbricht that we have made significant progress, and established that his daughter travelled back to London from Surrey, confirmed by cell site analysis of her mobile phone.’

That wasn’t quite true, but Gillard wasn’t about to contradict the chief constable in front of Beatrice’s father. There would hopefully be opportunities to put the more nuanced reality to him. Ulbricht shook the detective’s hand firmly, grasping his elbow with the other hand.

‘I’d like you to know, sir, that we are doing absolutely everything possible to find your daughter,’ Gillard said.

‘I am so grateful,’ Ulbricht said, in barely accented English. ‘For my wife and me, this is the most terrible experience. But we have an enormous depth of respect for the thoroughness, efficiency and expertise of the British police.’

Gillard wondered if he would be quite equal to that exalted level of expectation. ‘I understand that the Home Secretary will be here shortly, so I was hoping to grab a few minutes before so I might be able to ask you a few questions which would help us get some insight into Beatrice’s state of mind.’

‘Yes of course. I believe you have some CCTV footage of her, and I would like to see that too if possible.’

‘Certainly.’ Gillard steered the minister back to the conference room he had previously occupied, and brushed down a seat which had somehow accumulated crumbs. The two personal protection officers followed, one staying inside and the other out.