'Me.'

'That's right. David Umber. Sitting outside the Red Lion. With a ringside view of the whole thing.'

'I told you everything I knew at the time. Every single thing I could remember.'

'Which didn't amount to much. And the same goes for the rest. Confusion is the top and tail of it. No registration number for the van. No decent description of the abductor. No nothing. Result: one dead girl; one missing girl; one traumatized boy; one guilt-ridden nanny; a devastated family; a hamstrung inquiry; an unsolved murder. Maybe two unsolved murders. What happened to Tamsin… we have no idea.'

'You have no idea. Officially, it's down to Radd. That's still so, isn't it?'

'It's a grey area. He was never formally charged. But he did confess. The whole thing had a… desk-clearing feel about it to me.'

'What do you mean?'

'Nine years after the event, and only a few months after I've taken early retirement, Brian Radd, child murderer, suddenly adds Tamsin Hall to his admitted list of victims just before he goes into court certain of a life sentence. Says he drove her off, did God knows what to her, then strangled her and buried the body in Savernake Forest. Can't remember, even vaguely, which part of the forest, so a search is out of the question. They'd have found bugger all after nine years anyway. Radd's from Reading, so it's a Thames Valley case, but Hollins, my successor in Wiltshire – a by-the-book timeserver if ever there was one – goes with the flow and puts out a statement saying they're not looking for anyone else in connection with the crime. I smell a rat. Radd's confession gets the murder and the abduction off the books. Nobody cares whether it would stand up in court – whether it's true.'

'Sally cared.'

'Were you married by then?'

'No. Together. But not married. That came later.' Later as in too late, Umber thought but did not say. The marriage had been an attempt to deny that their relationship was falling apart. Its disintegration would have been easier to accept if the reason had been something banal like infidelity or incompatibility. But no. The reason was Avebury, 27 July 1981. That was always the reason. 'The police signing up to Radd's version of events really got to her, you know. She saw the bloke who grabbed Tamsin bundle her into the back of the van and climb in after her. Then the van took off. But Radd claimed to have been alone. No accomplice. Therefore Sally must have been mistaken. She'd been blamed for not taking better care of Tamsin. Now she was being told her account of what happened wasn't credible. She never got over that.'

'It would have been different if I'd still been on the Force.'

'Pity you didn't tell her so.'

Sharp scowled into his beer. 'My old Chief Super asked me not to rock the boat.'

'And you were a loyal cop, even in retirement.'

'I should have contacted Sally and assured her I still believed her.'

'Yes. You should.'

'Is that what made you do it?'

Umber was wrong-footed by the question. He had seemed to have Sharp on the defensive. It had not lasted long. 'Do what?'

Sharp stared at him long and hard. The server replaced their empty glasses with full ones. Sharp held the stare.

'What are you talking about?' pressed Umber.

'Remind me why you were at Avebury that day.'

'For God's sake.'

'Remind me.'

Umber sighed. 'All right. Here we go again. I was one year into a Ph.D at Oxford, studying the letters of Junius. I was spending the summer with my parents in Yeovil. I got a call from a man called Griffin, who said he was up in Oxford, had heard about my research and had something to show me which he thought would be helpful. We agreed to meet in the pub at Avebury that lunchtime. It's as simple as that. Though, as I recall, you never accepted the explanation at face value.'

'I kept my notebooks from the investigation. Took a look through them before I came out here. You're right. There were a lot of question marks in the sections relating to you. And question marks mean doubts.'

'Because Griffin never showed up? Well, you had road blocks up within half an hour. He must have got caught up in the traffic jam and… decided to turn round and go back to Oxford.'

'Plausible enough. But then why didn't he contact you again?'

Umber shrugged. 'I haven't a clue.'

'You had no phone number for him? No address?'

'He was… cagey. I assumed I'd get the details when we met.'

'How had he heard about your research?'

'He didn't say.'

'And you didn't ask?'

'I was more interested in what he was offering to show me.'

'Which was?'

'You already know. It's in your notebook, isn't it? All this stuff must be.'

'Junius was the pen name of the author of a series of anonymous letters to the press in the mid-eighteenth century blowing the lid on the politics of the day. A mole, I guess we'd call him now. Correct?'

'Yes. More or less.'

'What made him such a big deal?'

'For three years, from 1769 to 1772, he savaged the conduct of government ministers in the letters page of the Public Advertiser and succeeded in hounding the Duke of Grafton into resigning the premiership. The reading public lapped it up. Especially since he was clearly either a government insider or someone with access to extremely accurate inside information. But he was never unmasked. The mystery of his identity added to his appeal. And he quit while he was ahead. So, a fascinating figure.'

'What exactly were you researching about him?'

'His identity. The classic unanswered question. Recent historical opinion favours Philip Francis, a senior clerk in the War Office, as the culprit. I was aiming to put that theory to the test.'

'And did you?'

'I never finished.'

'Why not?'

Umber stared Sharp down. 'Something else cropped up.'

'Was it you or the mysterious Mr Griffin who suggested meeting at Avebury?'

'Griffin. But, Avebury being about halfway between Yeovil and Oxford -'

'It's a good bit closer to Oxford.'

'Is it? Well, he was the one doing me the favour. I wasn't going to quibble.'

'And the favour was?'

'After Junius gave up his letter-writing campaign, Henry Sampson Woodfall, the proprietor of the Public Advertiser, published a two-volume collected edition of the letters. He and Junius were in secret communication and Junius asked for a special vellum-bound, gilt-edged copy to be sent to him, which Woodfall duly arranged. It's never been seen since. If found, its provenance would obviously be a pointer to Junius's identity. Well, that's what Griffin claimed he had and was willing to show me: the specially bound copy, with, he said, a revealing inscription inside. It sounded too good to be true, but I wasn't about to pass up the chance, was I?'

'If Griffin had this… unique copy, why didn't he… put it up for auction or something?'

'He didn't say.'

'Why involve you, a…'

'Piddling research student?'

'You said it.'

'I don't know. He promised all would become clear when we met. But we never did.'

'Could it have been a hoax? Some fellow student of yours pulling your leg?'

'I don't think so.'

'Then what do you think it was all about?'

'I don't know.'

'Did you try to track Griffin down when you went back to Oxford?'

'I asked around, but nobody had heard of him. After what had happened at Avebury, though, it seemed so… trivial. I mean, Junius, who really gives a damn? I suppose that was one of the reasons why I gave up on the Ph.D.'

'And the other reasons?'

'They were mostly to do with Sally.'

'I was told she went abroad after the inquest.'

'So she did.'

'You went with her?'

'Yes.'

'I'm sorry… about her death.'

'Me too.'