‘Police,’ I yelled, ‘get out of the way!’ I didn’t yell ‘stop that dog’ — I do have some standards.

Toby whirred past the J. Sheekey Oyster Bar and the salt-beef and falafel place on the corner, and shot across the Charing Cross Road, which is one of the busiest roads in central London. I had to look both ways before crossing, but luckily Toby had stopped at a bus stop and was relieving himself against the ticket machine.

Toby gave me the smug, self-satisfied look employed by small dogs everywhere when they’ve confounded your expectations or messed on your front garden. I checked which buses used the stop — one of them was the 24: Camden Town, Chalk Farm and Hampstead.

Nightingale arrived, and together we counted cameras. There were at least five that had a good view of the bus stop, not to mention the cameras that Transport for London routinely mounts in its buses. I left a message on Lesley’s phone suggesting she check the camera footage from the 24 bus first. I’m sure she was thrilled when she got it.

She got her revenge by calling me at eight o’clock the next morning.

I hate the winter; I hate waking up in the dark.

‘Don’t you ever sleep?’ I asked.

‘Early bird gets the worm,’ said Lesley. ‘You know that picture you sent me, the one of Brandon Coopertown? I think he boarded a number 24 at Leicester Square less than ten minutes after the murder.’

‘Have you told Seawoll?’

‘’Course I have,’ said Lesley. ‘I love you dearly, but I ain’t going to fuck up my career for you.’

‘What did you tell him?’

‘That I had a lead on WITNESS A, one of several hundred generated in the last two days, I might add.’

‘What did he say?

‘He told me to check it out,’ said Lesley.