CHERUB campus was Sunday-morning quiet as a blonde twenty-two-year-old stepped up to a set of doors, dressed in tight-fitting cords and tatty Converse. She leaned forward, staring into a black square with a green light flashing above it. After a moment, a screen beneath the panel lit up with Lauren Adams, access granted.

The snaking mission control building on CHERUB campus had recently undergone refurbishment, with new floorboards and modern art. The heart of the building was a small control room aglow with computer screens. From here, the sixty or so CHERUB agents and their adult controllers who are on a mission at any given time can call in an emergency, request backup, equipment or a link to specialists whose skills range from hacking an encrypted file to making sure that a traffic light turns red when it needs to. Branching off were three smaller control rooms, which were manned during the critical phases of CHERUB’s individual missions.

After passing through, Lauren entered a broad corridor, with securely locked offices on one side and full-height glass overlooking forest on the other. Halfway along, a boy and a girl looked nervous in their grey CHERUB shirts, yet to hit their teens and about to get briefed on their first mission.

The last office had a sign Lauren found slightly ludicrous: James Adams – Mission Controller.

Before Lauren could knock, a stocky seventeen-year-old in a black CHERUB shirt opened the door and almost crashed into her with an armful of papers. After an exchange of sorries, Lauren stepped into a plush corner office, with bookshelves, trendy walnut desk and a pair of leather sofas either side of a coffee table.

The view, down a gentle slope over golden trees, was spectacular. Unfortunately, James Adams let down the ambience, dressed in gym clothes, one holed sock propped on his desk and surrounded by coffee mugs, box files and mounds of paper. He was on the phone, so he gave Lauren a thumbs-up and pointed her wordlessly towards a couch.

‘John …’ James told the phone. ‘She’s a sixteen-year-old girl and her whole wardrobe got smoked in the fire at the end of the mission. I just told her to get what she needed … I realise I should have set a budget, John. But how was I supposed to know she was going to go to London and spend eight hundred pounds on shoes?’

Lauren smirked as she slid a backpack down her arms, settling on the only part of the couch that wasn’t covered in files. As James continued talking, the black-shirt girl came back in with a roll of thick orange bags, which Lauren knew were for stuff that had to be incinerated on campus.

‘I’m Fu Ning,’ the girl told Lauren quietly, as James continued on the phone. ‘You must be his sister, Lauren.’

Lauren nodded. ‘My brother must be a pain to work for.’

Ning smiled. ‘He’s cool, just disorganised.’