But the drinkers moved first, three of them were up and blocking the way: obstructing his escape route. The big guy had been joined by a man with a denim shirt and muddy boots, and another guy with a Led Zeppelin singlet and tatts on his shoulders.

Jesus. What now?

His best choice was to just barge his way through, hope to reach the door and the light and freedom. But he made one more attempt at talking his way out.

‘Look – guys – sorry – por favor -’ It was useless; he was stammering. One of the cider drinkers was actually rolling up his sleeves.

‘Stop!’

David swivelled, and saw the blonde girl. She was physically interposing herself between David and his assailants – and she was talking very quickly to the men. Her smart and staccato Spanish was accented, and the words came too fast for David to understand.

Yet her intervention was…working. Whatever she was saying – it was succeeding. The anger in the men perceptibly dwindled; scowls became sullen glares, the cold angry faces sank back into the shadows. She was rescuing him from a nasty beating.

He looked at the girl, she looked at him, and then she looked right past him.

Now David realized – maybe there was another reason the guys had fallen back. Right behind him, a figure was walking across the room. If the drinkers had been calmed by the girl, they were positively cowed by this new figure emerging from the shadows. Where had he come from?

The man was tall and dark. His face was stern, half shaven, and mournfully aggressive. He was maybe thirty-five years old. Maybe an athletic forty. Who was this? Why had he silenced everyone?

‘Miguel…?’

It was the barman – gabbling nervously.

‘Er…Miguel…Eh…Dos equis?’

Miguel ignored the offer. He was gazing with his dark, deepset eyes directly at the blonde girl and David. He was standing close. His breath was tinged with some alcohol, strong wine or brandy. But he didn’t seem drunk. Miguel turned, and looked at the girl. His voice was deep and smooth.

‘Amy?’

Her answer was defiant. ‘Adiós, Miguel.’

She took David’s hand, and started pulling him towards the door. Quickly and firmly. But Miguel stopped her. He reached out – and simply grabbed Amy’s throat. Her fingers loosened from David’s grasp.

And then Miguel hit her. Hard. A shocking and brutal blow across the face. The girl fell to the floorboards, sprawling in the cigarette butts and screwed tapas napkins.

David gaped. This sudden violence, against a much smaller young woman, was so shocking, so utterly and casually outrageous, David was stunned. Immobile. What should he do? He gazed around. No one else was going to intervene. Some of the drinkers were actually turning away, giving each other weak and cowardly grins.

David leapt on Miguel. The Basque man may have been bigger and taller than David – and David wasn’t short – but David didn’t care. He remembered being beaten as a teenager. The angry orphan. People picking on the weak or vulnerable. Fuck that.

He had Miguel round the neck, he was trying to get room for a punch.

He failed. Grabbing this man was like riding a surging bull: the taller man stiffened, swivelled, and threw him contemptuously onto the floor. David grabbed at a bar stool, pulling himself to his feet. But then he felt another, quite absolute pain: he was being struck by something metal.

As the blackness descended, he realized he was being pistol-whipped.

Simon Quinn paid the cabbie, quit the taxi, and shot a glance along the stucco Georgian terrace. His laptop bag felt heavy on his shoulder.

The murder house was painfully obvious: two police vans were parked outside, with forensic officers in white paper suits offloading steel-grey Scene of Crime suitcases. Festoons of blue and yellow police tape roped off the frontage of the tall, elegant London terrace.

He felt a sudden twinge of apprehension. DCI Sanderson had described the murder as a…knotting. What the hell did that mean?

The nerves were palpable, indeed visible: a faint tremble in his hand. He’d attended a lot of murder scenes in his job – crime and punishment were his journalistic meat and drink – but that word…knotting. It was odd. Disquieting.

Ducking under the police tape he was met at the threshold by the bright young face of DS Tomasky. Sanderson’s new junior officer, a cheerful Londoner of Polish descent. Simon had met him once before.

‘Mister Quinn…’ Tomasky smiled. ‘Fraid you missed the corpse. We just moved her.’

‘I’m here because the DCI called me…’

‘Wants his name in the tabs again?’ Tomasky laughed in the pleasant autumnal sunshine. Then he stopped laughing. ‘I think he’s got some photos to show you.’

‘Yes?’

‘Yeah. Pretty gruesome. Be warned.’

Tomasky leaned an arm across the doorway, physically barring the journalist from entering the house. Beyond Tomasky’s arm, he could see two more forensic officers stepping in and out of a room, with their blue paper facemasks hanging loose.

‘How old is the victim?’

The policeman didn’t move his arm.

‘Old. From southern France. Very old.’

Looking up at the stucco frontage of the house, Simon glanced left and right.

‘Nice place for an old lady.’

‘Tak. Must have been wealthy.’

‘Andrew, can I go in now?’

DS Tomasky half-smiled.

‘OK. The DC is in the room on the left. I was just trying to…prepare you.’

The detective sergeant gestured Simon through the door. The journalist walked down the hallway, which smelled of beeswax and old flowers – and the gases and gels of forensic investigation.

A voice halted him.

‘Name of Françoise Gahets. Never married.’

It was Sanderson. His lined and lively face was peering around the door of the room at the end of the hallway.

‘DCI! Hello.’

‘Got your notebook?’

‘Yes.’ Simon fished the pad from his pocket.

‘Like I said, name of Françoise Gahets. She never married. She was rich, lived alone…We know she’s been in Britain sixty years, no close relatives. And that’s all we’ve got so far. You wanna see the SOC?’

‘Unless you want to get, ah, pizza.’

Sanderson managed a very faint smile.

They crossed the doorway. As they did Sanderson continued:

‘Body was found by the cleaner yesterday. Estonian girl called Lara. She’s still downing the vodkas.’

They stepped to the end of the sitting room. A white-overalled, white-masked forensic officer swerved out of the way, so the two men could see.

‘This is where we found her. Right here. The body was moved this morning. She was…sitting right there. You ready to see the photos?’

‘Yes.’

Sanderson reached to a sidetable. He picked up a folder, opened it, and revealed a sheaf of photographs.

The first photo showed the murdered old woman, fully clothed, kneeling on the floor with her back to them. She was wearing gloves, oddly enough. Simon checked the photo against the reality in front of him.

Then he looked back at the photo. From this angle the victim looked alive, as if she was kneeling down to search for something under the TV or the sofa. At least she looked alive – if you regarded her up to the neck only.

It was the head that made Simon flinch: what the murderer, or murderers, had done to the head.

‘What the…’

Sanderson offered another photograph:

‘We got a close-up. Look.’

The second photo was taken from a few inches away: it showed that the entire top of the victim’s scalp had been wrenched away, exposing the white and bloody bone of her skull.

‘And check this one.’

Sanderson was proffering a third image.

This photo showed the detached scalp itself, a bloody clogged mess of wrinkled skin and long grey hair, lying in the carpet; rammed through the hair was a thick stick – some kind of broom handle maybe. The grey hair was tightly wound around this stick, many many times, all twisted and broken. Knotted.