The City of Brighton and Hove had so many different faces, Grace thought, and so many diverse people. It seemed that some cities were divided into different ethnic communities, but here in Brighton and Hove it was more like different sociological communities.

There were the genteel elderly, in their mansion blocks or sheltered housing, who on summer days could be seen watching the cricket at the County Ground or playing bowls on the Hove lawns, or sitting in chairs on the promenade, and the beaches in summer, and, if they had the funds, wintering in Spain or the Canaries. And the poorer elderly, shivering out the winter – and half the summer – imprisoned in their damp, dank council flats.

There were the in-your-face wealthy middle classes with their smart detached houses in Hove 4, and the more discreet, in the handsome seafront mansion blocks. And the more modestly off, like Grace, in homes spread out to the west to the suburb of Southwick, directly behind the commercial port of Shoreham Harbour, and in pockets all over the city and stretching well out to the Downs

Much of the colour and vibrancy of Brighton and Hove came from the very visible, and often brash, gay community, and the wall-to-wall students, from Sussex and Brighton Universities and the plethora of other colleges, who had colonized whole areas of the city. There were the visible criminals – the drug dealers lurking on the scruffier street corners, who would melt into the shadows at the smell of a police car – and the less visible ones, the rich ones at the top of their game, who lived behind high walls in the swanky houses of Dyke Road Avenue and its tree-lined tributaries.

Council estates fringed the city; the two biggest, Moulscombe and Whitehawk, had long had reputations for crime and violence, but in Grace’s view these were not particularly deserved. There were crime and violence all over the city, and it made people feel comfortable to point a finger at these estates, as if there was an altogether different species of Homo sapiens living there instead of mostly decent folk who didn’t have enough money to buy themselves smugness.

And there was the sad underclass. Despite regular attempts to remove them from the streets, the moment the weather warmed up, the winos and the homeless drifted back to the shopfronts, porches, pavements and bus shelters. This was bad for tourism and even worse for the city’s conscience.

From the start of the festival in May and the arrival of spring, tables and chairs appeared outside every cafe, bar and restaurant, and the streets of the city came alive. Some of those days, Grace thought, you could almost imagine you were on the Mediterranean. Then a weather front would move in off the Channel, a howling south-westerly accompanied by punishing rain that would drum on the empty tables and lash the windows of boutiques filled with mannequins in beachwear, as if mocking anyone who dared to pretend that England ever actually had a summer.

The beating downtown heart of the city, through which they were travelling now, was concentrated in a square mile or so either side of the Palace Pier. There were the tightly packed Regency terraces of Kemp Town, in one of which Janie Stretton had lived; the Lanes, where the antique dealers were centred; and the North Laines district filled with small, trendy shops and tiny town houses, among which was the converted factory building where Cleo Morey had her flat.

Nick Nicholl drove the unmarked Ford Mondeo. Grace sat in the front passenger seat, busily making notes on his Blackberry. Norman Potting was in the back. They were driving down the London Road in the centre of Brighton. At most times of the day or night they would have been crawling along in dense traffic, but early on this Sunday morning, apart from a couple of buses, they virtually had the road to themselves.

Grace checked his watch. Hopefully this interview with Reggie D’Eath would not take long, and he could squeeze a couple of hours out of the day for his god-daughter. Enough to take her to lunch, if not to the giraffes today.

They were passing the Royal Pavilion, the city’s most distinctive landmark, on their right. None of the three men looked at it – it was one of those places that was so familiar it had become all but invisible to them.

The turreted and minareted building in the style of an Indian palace was commissioned by George IV when Prince of Wales, as a seaside shag-palace for his mistress, Maria Fitzherbert, in the late eighteenth century. And as seaside shag-palaces go, nothing quite so grand had probably been built anywhere in the world, ever since.

They stopped at the roundabout at the intersection with the seafront, with the Palace Pier, garish even early on a Sunday morning, opposite them. A leggy blonde in a skirt that barely covered her buttocks crossed in front of them unhurriedly, throwing them a flirty glance and jauntily swinging a bag.

Potting, who had been quiet for some minutes, murmured, ‘Come on, doll. Bend over; show us your growler!’

There was a gap in the traffic, and Nick Nicholl turned left.

‘She’s all right, she is!’ Potting said, turning to watch her out of the rear window.

‘Except she is a he,’ Nick Nicholl corrected him.

‘Bollocks!’ Potting said.

‘Yes, exactly!’ the DS retorted.

They drove along Marine Parade, past the debris of broken glass and food cartons outside a nightclub, the über-trendy Van Alen apartment building, then the black and white flinted Regency facades that fronted the imposing crescent of Sussex Square, where, Glenn Branson had told Grace a thousand times, Laurence Olivier had once had a home.

‘You’re talking through your arsehole,’ Potting replied. ‘She was gorgeous!’

‘Big Adam’s apple,’ the DS said. ‘That’s how you tell.’

‘Fuck me,’ Potting said.

‘I’m sure he would have done, if you’d asked nicely.’

‘Shouldn’t be allowed out on the streets looking like that, bloody fudge-packer.’

‘You are so gross, Norman,’ Grace said, turning round. ‘You are quite offensive, you know.’

‘Well I’m sorry, Roy, but I find poofs offensive,’ Potting said. ‘Never understood ’em, never will.’

‘Yes, well, Brighton happens to be the gay capital of the UK,’ Grace said, really irritated with the man. ‘If you have a problem with that you’re either in the wrong job or the wrong city.’ And you’re a complete fucking prat, and I wish you weren’t in my car or in my life, he would have liked to have added, digging in his pocket for some more paracetamol.

On their left they passed terrace after terrace of imposing white Regency houses. On their right were the sails of a dozen yachts, fresh out of the Marina on a Sunday race.

‘So this bloke we’re going to have a chat with,’ Potting said. ‘Reginald D’Eath, is he one of them, too?’

‘No,’ Nick Nicholl said. ‘He isn’t – he just likes girls – as long as they’re not older than about four.’

‘That’s something I really can’t understand,’ Norman Potting said.

Popping a pill from the foil pack, Grace thought grimly, Great, at last we’ve found something in common.

They drove up a steep hill at the back of Rottingdean, alongside a prep school playing field with a cricket pitch marked out in the centre and two large white screens on rollers, with pleasant detached houses opposite. Then they turned into a street with bungalows on either side. It was the kind of quiet area where anything out of the ordinary would stand out – as the bright yellow Neighbourhood Watch stickers, prominently displayed in each front window, warned.

A good choice of location for a safe house, Grace thought, except for one minor detail that appeared to have been overlooked. Who in their right bloody mind would put a paedophile in a house a few hundred yards away from a school playing field? He shook his head. Didn’t anybody ever think?