‘I fail to understand,’ she said.

‘I’m afraid this sack would appear to contain waste from your own household, Mrs Julian,’ said the sergeant. ‘In other words to have been yours and been disposed of from your premises.’

Mrs Julian sat down. She sat down rather heavily on one of the bentwood chairs and fixed her eyes on the opposite wall and felt a strange tingling hot sensation in her face that she hadn’t experienced for some sixty years. She was blushing.

‘I see,’ she said.

The constable began stuffing the garbage back into the sack. Mrs Upton watched him, giggling.

‘If you haven’t consumed all our stock of sherry, Mrs Upton,’ said Mrs Julian, ‘perhaps we might offer these two gentlemen a glass.’

The policemen, though on duty – which Mrs Julian had formerly supposed put the consumption of alcohol out of the question – took two glasses apiece. They were not at a loss for words and chatted away with Mrs Upton, possibly on the subject of the past and future exploits of Stewart. Mrs Julian scarcely listened and said nothing. She understood perfectly what had happened, Mr Arnold changing his clothes because they were wet, deciding to empty his rubbish that night because he had forgotten or failed to do so on the Saturday morning, gathering up his own and very likely Mr Laindon’s too. At that point she had left the window to go to the telephone. In the few minutes during which she had been talking to her nephew, Mr Arnold had passed her gate with his barrow, lifted the lid of her dustbin and, finding a full sack within, taken it with him. It was this sack, her own, that she had seen him disposing of on the tip when she had next looked out.

No wonder the boiler had hardly ever been alight, no wonder the compost heap had scarcely grown. Once the snow and frost began and she knew her employer meant to remain indoors, Mrs Upton had abandoned the hygiene regimen and reverted to sack and dustbin. And this was what it had led to.

The two policemen left, obligingly discarding the sack on to the tip as they passed it. Mrs Upton looked at Mrs Julian and Mrs Julian looked at Mrs Upton and Mrs Upton said very brightly: ‘Well, I wonder what all that was about then?’

Mrs Julian longed and longed for the old days when she would have given her notice on the spot, but that was impossible now. Where would she find a replacement? So all she said was, knowing it to be incomprehensible: ‘A faux pas, Mrs Upton, that’s what it was,’ and walked slowly off and into the living room where she picked up her knitting from the chair by the window and carried it into the furthest corner of the room.

As a detective she was a failure. Yet, ironically, it was directly due to her efforts that Mrs Arnold’s murderer was brought to justice. Mrs Julian could not long keep away from her window and when she returned to it the next day it was to see the council men dismantling the tip and removing the sacks to some distant disposal unit or incinerator. As her newspaper had told her, the strike was over. But the hunt for the murder weapon was not. There was more room to manoeuvre and investigate now the rubbish was gone. By nightfall the weapon had been found and twenty-four hours later the young out-of-work mechanic who had struck Mrs Arnold down for the contents of her handbag had been arrested and charged.