‘Because Diall had to go there on more than one occasion to pick up Marsh. He made a little ditty about it. Now how did it go?’ He scratched his head. ‘Ah, yes. “Twenty-two Trumpton Avenue houses the witch who hasn’t a clue. Vodka, rum, Bacardi and…” No, wait. “Rum, vodka, gin…”.’ He frowned. ‘No. Hang on. I’ll have it in a minute.’

‘I think we’ll manage without it,’ Winter said drily. ‘Thanks for your time.’

Tobias was still mumbling and humming to himself as we walked away.

‘He’s the culprit,’ I said as soon as we were at the end of the corridor. ‘Tobias Worth-Jones is the guilty one for sure.’

Winter sighed. ‘Why?’

‘First of all,’ I said, ticking off my fingers, ‘he’s eating lunch at his desk. He doesn’t have enough time to take a break because he’s spending all his free time reading Volume 9. Secondly, he knew Diall well enough to get all the gossip about him, so he definitely knew him well enough to be invited into his home where he murdered him. Thirdly, his tie has yellow stripes. Never trust someone wearing yellow.’

‘What’s wrong with yellow? It’s the colour of sunshine.’

‘It makes me look sallow and washed-out.’ Winter took a deep breath and I grinned. ‘Are you counting to ten?’

‘Your theories are quite extraordinary, Ivy. Besides, I thought you were convinced that Price did it.’

‘I changed my mind. It’s a lady’s prerogative.’

Winter halted abruptly. Slowly, he turned towards me. ‘You … you’re a lady?’

Ha. Ha. Ha.

***

Trumpton Avenue sounded considerably more upmarket than it actually was. Instead of a leafy road with pretty Victorian houses, which is what I’d imagined, Winter and I found ourselves in Oxford’s version of hell. Although I’m sure that the council serves this area in the same way as the rest of the city, the road was strewn with rubbish ranging from old beer cans to cigarette ends.

On one side of the street, a shabby man mumbled to himself as he shuffled along. When he saw us he yelled a warning about two-headed sheep then shook himself and continued on his way. A scrawny cat, thankfully ginger rather than black, crossed our path and gave a defiant hiss in Winter’s direction. The houses were small, often with boarded-up windows. They were also covered in a layer of grime which archaeologists would probably find fascinating.

‘I bet they don’t put this place in the tourist brochures,’ I said.

Winter didn’t answer though he appeared horrified. It didn’t help when we discovered that number two wasn’t before house numbers four and six, as you might expect. No, that would have been too easy. Instead, it was wedged in a terrace further down, as if the town planner had been having some fun and decided to rewrite the laws of basic arithmetic.

Winter gently nudged me out of the way so that he was the only person on the doorstep when he rang the bell. I picked some dirt out of my fingernails. If he was so keen to do all the work, let him get on with it. My mouth was parched and my sock was still wet. At this rate, I wouldn’t have to feign illness; I’d end up in hospital with pneumonia. Or some kind of terrible bacterial infection.