He headed past the City Hospital and ended up on the Esplanade: a long expanse of grass links with bowling green, tennis and putting. There were amusements, all closed this early. People were on the Esplanade – jogging, walking their dogs, morning constitutionals. Rebus joined them. Groynes divided the mostly sandy beach into neat compartments. It was as clean a part of the city as he’d seen, excepting the graffiti – an artist called Zero had been hard at work, making this his or her personal gallery.

Zero the Hero: a character from somewhere … Gong. Jesus, he hadn’t thought of them for years. Pot-head pixies with stoned synths. Floating anarchy.

At the end of the Esplanade, next to the harbour, stood a couple of squares of housing, a village within the city. The squares themselves comprised drying greens and garden sheds. Dogs barked a warning as he passed. It reminded him of the east neuk of Fife, fishermen’s cottages, brightly painted but unpretentious. A taxi was cruising the harbour. Rebus waved it down. The R&R was over.

There was a demo outside the headquarters of T-Bird Oil. The young woman with the braided hair who’d been so persuasive the previous day was sitting cross-legged on the grass, smoking a roll-up, looking like she was on her break. The young man currently on the megaphone didn’t have half her anger or eloquence, but his friends cheered him on. Maybe he was new to the demonstrating game.

Two young woolly suits, no older than the activists, were in consultation with three or four environmentalists in red boiler-suits and gas masks. The policemen were saying that if they took the gas masks off, conversation might be less of a chore. They were also asking that the demonstration move off land owned by T-Bird Oil. Namely, the patch of grass in front of the main entrance. The demonstrators were saying something about the laws of trespass. Legal knowledge came with the territory these days. It was like rules of unarmed combat to a squaddie.

Rebus was offered the same literature as the day before.

‘I already took,’ he said with a smile. Braid-hair looked up at him and squinted, like she was taking a photograph.

In the reception area, someone was videoing the demo through the windows. Maybe for police intelligence; maybe for T-Bird’s own files. Stuart Minchell was waiting for Rebus.

‘Isn’t it unbelievable?’ he said. ‘I hear there are groups like that one outside each of the Six Sisters, plus smaller operations like ours.’

‘The Six Sisters?’

‘The big North Sea players. Exxon, Shell, BP, Mobil … I forget the other two. So, ready for the trip?’

‘I’m not sure. What are my chances of getting a kip?’

‘It might be pretty bumpy. Good news is, we’ve a plane heading up, so you’ll be spared a budgie – at least for today. You’ll fly in to Scatsta. It used to be an RAF base. Saves the hassle of changing at Sumburgh.’