He grabbed his brown coat off the sofa arm, jumped nimbly up and strode out of the room. In the hotel lobby, without stopping, he stretched out a hand for a brown trilby on a hatstand and skipped down the front steps, Patrick trailing in his wake. A sharp shower, filtered through arrows of sunlight, was bouncing shiny pellets of water off the pavement. J put on the trilby and turned to Patrick. ‘Important lesson of life, never be caught without a hat.’ A hundred yards or so down Cromwell Road, he made the diagonal turn into Lexham Gardens. Patrick peered up through the rain to the tall terraces of stucco-fronted Victorian houses. Perhaps it was J’s presence that moved him to see them as a box-set of anonymous hidey-holes for the affluent; the sort of place where a certain sort of gentleman might house his mistress – or an intelligence agency its spy.

J stopped at the seventh house on the south-east side of the street and descended the basement steps. The external door opened before him; he entered, waving Patrick in with uncharacteristic energy. A lean-faced, wiry figure dressed in a chauffeur’s uniform, his black hair greased down to preserve a crisp parting, glanced out and closed the door.

‘Good morning, Len,’ said J.

‘Good morning, Mr J,’ came the reply in a strong Ulster accent. For some reason, Patrick instantly imagined him as J’s one-time silent assassin.

‘This young man is called Patrick, we’ll be seeing more of him.’

Len stuck out a hand. ‘Pleased to meet you, sir.’

Patrick read the ‘sir’ as the gnarled sergeant-major’s nod to the raw officer cadet. He realised he hadn’t asked J the obvious question. ‘You never said why you’re bringing me here.’

‘Didn’t I?’ he replied ingenuously. ‘Kareem’s asked to see a solicitor.’

‘A solicitor?’

‘Yes, thought you’d have figured that out.’

‘Whose side am I on?’

The reply was raised eyebrows. ‘You’re about to meet the person in charge of this little operation,’ said J. ‘Ask her if you want.’

‘Aren’t you?’

‘Good lord, no, I’m a mere outrider these days with the occasional idea.’

‘Anyway, what operation?’

J grinned. ‘Stuff you don’t need to know, Patrick. She’s called Isobel Le Marchant, rising star of the service. If she gets this right, she’ll be headed straight for the top.’

They walked down a passage past a study-like room – Len’s domain, Patrick assumed – then an opening into a kitchen, followed by a closed door. J opened it, switched on the light and peered in, Patrick at his shoulder. It was a large bedroom, no window, two abstract paintings on stone-coloured walls, an en-suite bathroom leading off. The bath, shower and basin taps were gold; a scent of lavender sweetened the enclosed air. ‘Gloriously vulgar,’ said J. He scanned both rooms. ‘Just want to make sure someone’s bleaching the loo.’