Gillard was expecting a call from Dr Delahaye, but when he picked up the phone the switchboard operator said it was someone from the Hyacinth Trust, who had asked for him by name.

The detective sighed and agreed to take the call. He knew the organisation, originally the Society of Murder Victims and one of the largest and most active of the many victims’ organisations. He didn’t catch the woman’s name, but it was clear she had a prepared script. ‘As you know, we have campaigned long and hard to make sure that those who commit the worst crimes are never released early from prison.’

‘Well, perhaps if I could stop you there. I’m not involved with the decision. Perhaps you should direct your call towards the probation service—’

‘I’m sorry, Mr Gillard,’ she said. ‘I’m ringing you because I understand it was you who originally caught Neville Rollason.’

‘Where did you hear that?’ Gillard wasn’t aware that this was generally known.

‘It was in the Croydon Advertiser back in October 1988. I’ve got a cutting. The article doesn’t mention you by name, merely that a twenty-one-year-old new recruit made the arrest, but I was able to find out through some contacts that it was actually you.’

‘I’m sorry, I didn’t catch your name,’ Gillard said.

‘I’m the mother of Robert Fenwick,’ she said.

‘Ah, Mrs Fenwick, what can I do to help?’ The detective realised he had spoken to her before, years ago. Thirteen-year-old Robert Fenwick disappeared from his home in 1986 and was never seen again. It was one of the coldest of cold cases in Surrey police history. His old boss Paddy Kincaid had reworked it several times but never got anywhere. Gillard recalled the slim and fashionably dressed redhead appearing at a press conference arranged by Kincaid during the early days of the search for her son. She would be in her late fifties now.

Mrs Poppy Fenwick had rung to speak to Paddy on numerous occasions, to see if progress had been made. But very often Paddy would ask Gillard, then simply a detective constable, to take the call and listen to her pour her heart out. He had, on his own initiative, sent a remembrance card on behalf of Surrey Police to Mrs Fenwick on the fifth anniversary of the boy’s disappearance, assuring her that the hunt for the killer had not been forgotten. The trouble was it had been forgotten, and subsequently tucked away into a bureaucratic cul-de-sac. He was aware that the Hyacinth Trust had been pushing the theory that Neville Rollason killed Robert and another boy, John Dawson, in the Croydon area. It had never been given much credence, despite Croydon being where Gillard had arrested Rollason, and where the murderer had been renting a flat from June 1986 to the moment of his arrest in 1988.