Williams was on the way to do a job in India when the Japanese invaded Malaya and Singapore and she was, as she said, 'put in the bag' in February 1942. She spent three and a half years imprisoned by the Japanese, five months of this time in a cage 6ft 4in square with three men and a lavatory in the corner. There was a gnomic sign that said: 'No membling (sic), preaching or grooming.' When I met her in 1976 she still had a disconcerting habit of referring to so- and-so 'in the next cage to me', rather as one might to someone at the next desk in the office.
I wrote down what she said. 'It was so shocking, you thought the shock would kill you but it didn't. You got used to it. You thought you would rather die of thirst than drink from a lavatory used by people you knew had dysentery, but you drank all the same. A surprising number of us survived, the women better than the men, but perhaps we had better food. Some of the men committed suicide which the Japanese didn't like - a reflection, I suppose, on their entertainment.'
She still kept, and brought out to show me, a small faded cotton bundle. Wrapped in it were her possessions from those years: a blue tin mug with her initials 'CDW', a man's metal trouser button with which she cut her toe- nails and a polished wooden splinter with which she used to clean her teeth. She went straight back to Malaya to work eight months after her release but it was two years before she could bear to be parted from the metal button and the wooden splinter.
'I suppose one was very queer,' she said. 'When I found I could leave the house without those things I knew I was going to be all right. I'm rather like Dr Manette in A Tale of Two Cities who kept the cobblers' things he worked with in prison, and when he felt depressed he used to take them out and look at them.'
She believed, incidentally, that medicine was best practised in the home where you could see what went into the cooking pot - and certainly outside hospitals. 'Medical students used to be apprenticed to other doctors to 1880 but now all medical training is done in hospitals. I think it's rather like being an ornithologist who only looks at birds in cages. If you read Dickens or Thackeray there's no mention of hospitals; none of my four grandparents were in hospital in their lives.'