He left the detective block and wandered into the refectory. The lure of a fry-up was impossible to resist, the unhealthier the better. Crispy bacon, sausages, mushrooms, toast, possibly baked beans. And eggs, the full English cardiac arrest. There were only two in the queue ahead of him and he looked across the hot steel shelf into the bustle of the kitchen beyond wondering where Iris, his early morning friend, had got to.

‘I think it might be her day off,’ said his colleague.

Gillard leaned across the warm counter and asked a woman who was cleaning the coffee machine what had happened to Iris. ‘She normally works on a Saturday doesn’t she?’

‘Didn’t you hear?’ the woman replied. ‘She’s been off sick for days. I think there’s a card if you want to sign it.’

Gillard waited while the circulating card was traced and brought to his table. He looked through the many signatures and the ‘get well soon’. One signatory had said ‘I hope they get whoever did this to you.’ The signature was illegible.

Alarmed, Gillard signed his name, and then took the card back to the counter and asked to speak to the manageress. Mrs Ho, a tiny Chinese woman, emerge from the office and came up to him. ‘Can I ask you what happened to Iris?’ he asked her.

‘She was mugged at a bus stop.’

‘How awful,’ Gillard said. ‘Has no one been to see her?’

It was a two-hour errand, but definitely worthwhile. Iris McQueen lived in a Victorian terraced house in Staines, just a few streets away from DI Mulholland’s house. Before making the trip he’d read the brief and the sloppily-written crime report which said two young white males had shouted racial abuse at her while she was waiting to catch the bus, then approached, snatched her handbag and pushed her over. The attack was five days ago but no e-fit pictures had yet been issued, nor any follow-up action recorded.

Gillard rang the doorbell, and a tall West Indian youth opened it and eyed Gillard nervously. ‘You must be Josh,’ Gillard said, introducing himself. ‘How is your mum?’

‘I’m fine,’ said a loud and familiar voice from inside. ‘Is that my favourite detective?’

‘She’s okay,’ Josh said with a smile, beckoning the detective inside. ‘Do you want a cup of tea?’

Gillard accepted, and walked into the neat but rather over-furnished lounge. There were lots of photographs of smiling youngsters on the wall and on every surface. A Jamaican heritage was proudly proclaimed.

Iris was sitting on the settee wearing a housecoat with a bandaged leg extended onto a foot stool. ‘They told me I have got to keep my weight off it. But, boy, it is so sore.’

Establishing that there had been no further contact from the police, Gillard said: ‘This really isn’t good enough. I’ll contact PC Bennett and see what they can do. The report said you lost your house keys. Was the address with them?’