The downside of the open office was lack of privacy. The lavatory cubicles were too small to change in, and more than once, Tennant had to ask his staff to stand guard while he slipped out of his suit in an empty meeting room before a press conference or public meeting. More than once, a DC had done a quick about-turn at the sight of the boss in his underpants.

The call to the National Security Adviser – the Prime Minister’s adviser on terrorism – had gone well. Downing Street had called a COBRA crisis meeting for 3pm, but it would be brief, as it always was in the aftermath of an attack like this. There wasn’t going to be much to report, particularly if this was the work of a lone actor, and brief was good in the current political climate.

COBRAs had been challenging enough before the general election. But over the last nine months, with the influx of People’s Party members into the new coalition government, the point scoring had escalated to new heights of inanity. He threw his mind back to his last encounter with politicians: the National Security Council a couple of weeks earlier. These were supposed to be routine meetings, a chance for cabinet ministers to chew the fat with the heads of the security agencies – MI5, GCHQ, the Chief of the Defence Staff and SO15. But the agenda had been hijacked by Lesley Hogarth, the new deputy prime minister and leader of the People’s Party, who had rounded on the director general of GCHQ over some spurious Russian cyberwarfare story in the Sunday papers. It had been frivolous and embarrassing.

Tennant glanced at his watch, a present from Chris last birthday. The PM would want an early briefing before COBRA within the hour. But before that, he needed his own update. The discovery that Sophie Gabriel was on the case was welcome news. He had not spoken directly to Gabriel for six months, but she always impressed him, and he kept one eye on her career. He pulled out his phone and pulled up WhatsApp. Sophie, he messaged. Appreciate you’re snowed under – anything you’ve got would be helpful before COBRA. Technically, he shouldn’t be speaking to Gabriel directly. There were three ranks between them, and Gabriel’s commander would be livid if he found out he was arcing the chain of command. But what he didn’t know wouldn’t hurt him.

Ten minutes later, his phone buzzed.

‘Sophie, good to hear from you,’ he said. ‘It’s been a while. Ray well?’

‘He’s fine, sir,’ said Gabriel. ‘Still determined to sneak The Clash into the year seven music curriculum. So far the head of music doesn’t seem to have noticed.’ Tennant smiled. He’d met Gabriel’s husband at a Christmas party a couple of years earlier and had instantly liked him. They’d spent ten minutes arguing over the merits of The Ramones.

‘Sorry to arc like this, but I’m in Downing Street shortly,’ said Tennant. ‘What’s your take? One for us?’