‘Sorry to call late, ma’am, but I’ve an update on the NRF rifle,’ said Bose.

Gabriel was half-expecting the call. Bose had been liaising with the Ministry of Defence Police earlier that evening. The MDP were a tiny force, with no more than two thousand five hundred staff, based at a former US Air Force base in Essex with responsibility for protecting military sites.

‘The MDP has identified a prime suspect, the head armourer at Hedingly Barracks,’ said Bose. ‘He’s a Sergeant Christopher Jones. We’ve got more than enough on him, so I’ve arranged a team to go down at dawn to bring him in and pull his flat apart. MDP will provide support.’

‘Good work, Eva,’ said Gabriel. ‘Bring him up to St Pancras – I’d quite like to listen in to the interview myself.’

She hung up with a smile. A slightly smug smile, she conceded as she studied her face in the bathroom mirror. But deservedly so. Interviews with their two Leeds terrorists – Rod Houghton and Doug Glenister – had gone nowhere. And the search of both men’s homes had yet to yield anything of significance. But this Sergeant Jones could be the break they needed to crack into the NRF – and maybe even start to unravel the leadership.

DAY 12

Sunday

King’s Cross Police Station, North London

The constable from the Military Defence Police fiddled with his wispy moustache as Gabriel and Campbell approached the door to interview room two. Gabriel avoided looking at the moustache, worried her face might crack into a smile.

‘I’m going to watch,’ she said, handing over a file to Campbell. She walked into the next-door room and settled down behind the two-way mirror. She knew these rooms well, with their drab, stark interiors and stench of sweat and coffee.

Staff Sergeant Christopher Jones, the armourer from Hedingly Barracks, sat facing her through the glass, his hands folded on the battleship-grey table. His shrew-like solicitor, with narrow eyes and a tongue that seemed to be forever licking his lips, sat to his right.

Campbell started the digital recorder and gave the introductory legalese.

‘Staff Sergeant Christopher Jones, you have been arrested for the unlawful supply of Section One firearms,’ he continued. ‘The details of which are an unregistered SA80 assault rifle discovered at the scene of a major terrorist incident in Leeds yesterday afternoon. Can you confirm that you’re the armourer at the Hedingly Barracks, Hampshire? Correct?’

Jones gave a curt yes.

‘How long have you worked at Hedingly?’

‘Four years.’

‘And your job is what exactly?’

‘Armourer. Repairing, maintaining and modifying weapons as needed. I check them out for training and check them back in.’

‘And it’s also your role to order spares, is that right?’ he said.

‘That’s right.’

‘Could you have a look at this document, please? It’s a summary of the spares requisitions for the last three years. For the record, I’m passing Sergeant Jones a document marked as exhibit AM/7. Notice anything unusual?’

Jones studied the papers and shook his head. ‘Nope.’