The square had been cordoned off by the time he got there, and four uniform were keeping onlookers back. Four fire engines were on the scene, and the firefighters were both attacking the main blaze and working to keep it from spreading into adjacent buildings. He had always found fires terrifying, to look at, to smell, to deal with, since he had been involved in a massive blaze in the Docklands, in which seven people had died and the whole thing had taken two weeks to burn out. Now, as he dipped under the rope and went cautiously across the square, he felt the heat on his face, smelled the acrid burning.

The fire chief turned and nodded. Serrailler had worked with him only once before and knew him to be very competent.

‘Do you know anything at all yet?’

‘Not much except that three separate people reported hearing some sort of explosion – one said it was the same sound as an oil drum he’d once heard going up. Whether there was anything inside the shop that was combustible I don’t know yet – could have been something electrical.’

‘Or . . . ?’

‘Or could have been arson, something thrown into the shop, left in there – impossible to say just yet. Anything you know?’

‘Possibly. The place has been under surveillance since the body of a young junkie was found in the flat above a few weeks ago. The pharmacy belongs to a man called Wang Lin.’

‘He doesn’t live above?’

‘No, in Bevham. Assuming he’d left around five as usual, there’d have been nobody in the building.’

A sudden shout, and a great spurt of fire burst out of the roof and skywards.

‘I’m needed. We have to evacuate this whole side plus all the houses up the hill behind.’

Simon moved back. The square was like a film set, a moving scene of men with hoses, pipes, walkie-talkies, the noise of water under massive pressure pushing into the flames, voices shouting orders. Crackling. Sudden small explosions. Bangs. More shouts. Engines running on all sides.

‘Thought you’d have got here.’ Kieron had come up behind him. ‘Anyone inside?’

‘Probably not but they can’t get anywhere near to find out yet.’

‘Maybe I should have given you that twenty-four-hour surveil-lance.’

‘Hindsight’s a wonderful thing, sir.’

‘Think it’s accidental?’

‘No, but there’s nothing to say it isn’t either. They’ve got their hands full with keeping people away and organising an evacuation, but I need to ask if anyone reported lights in the shop. This place is dead after six in winter, though, so the chances are nobody was around to see anyway.’

‘Is the chemist here yet? Presumably he’d gone home by the time it started.’

‘Pray he had but I don’t know any more. Someone has to contact him if they haven’t already.’