Without warning, at the age of 10, Anne Watts was introduced to her 'new' mother. But what had happened to the old one?

As we stood in the hall next to our hastily packed little bags, we looked around for Mummy. I climbed the stairs two at a time, flew into the bedroom where she lay, fully dressed on the neatly made bed. Tendrils of her black hair curled damply on her forehead. Her eyes were closed. "Bye, Mummy, see you soon." A quick kiss on her cheek and off I went, without a backward glance.

My sister Susan and I were in the care of "Auntie" Eileen, the kindly sister of the scolding cook. With the trusting naivety of children we had jumped with joy at the offer of a holiday in Liverpool with her and "Uncle" Stan, leaving our mother and father behind.

Excitement built steadily as the car sped through spectacular Welsh countryside. Finally, Stan's comfortable old banger swept off a busy street and came to a halt in front of a large grey place that looked more like a school than a holiday destination. Confusingly, Uncle Stan chose to remain in the car and, after a quick hug and a kiss from him, we followed Eileen into the large draughty entrance hall clutching our few belongings. Here Eileen kissed us tearfully, quickly signed some papers and left us sitting confused on a bench outside an office door.

Bewilderment turned to panic as we were led off to a bare room where a grim-faced woman examined us for nits, and teeth and fingernails for "filth". We were washed roughly and dressed in strange clothes before being separated and led off to dorms where there were lots of other strange girls. Susan was five and I was nine, and we were alone, seemingly abandoned by our parents.

It hadn't always been like this. Born in Liverpool in June 1940, with Hitler throwing all that his Luftwaffe had to offer at Britain, I had been evacuated to the safe mountains of North Wales with my mother. Clare Rosetta was a dedicated nurse, wife and mother. My swashbuckling father, Arthur Frederick, was a merchant navy captain, a glamorous figure, appearing sporadically, all hugs and shiny buttons, bearing gifts and tall tales from exotic lands. So my war years were happy and carefree in a pretty little village near Snowdonia.

On 8 May 1945 there was joy and celebration in Europe as the war ended. "Daddy's coming home" was my mother's ecstatic cry and, sure enough, in 1946 my father retired from the sea and began transforming our home into a family hotel. My sisters Susan and Joan were born in 1945 and 1947.

Then Father employed Edith Rigby, a brilliant cook, to enhance the reputation of the hotel. She had a terrible temper. She also seemed friendly with Daddy and we quickly learned to keep away from the kitchen.

After her arrival, the easy nature of family life began to change. Mother's health seemed to decline. Visits to "heart specialists" in Liverpool were mentioned in hushed tones. Occasionally, raised voices could be heard echoing up the stairs. I would creep out in my nightdress and sit hugging my knees, face pressed against the banisters, frightened but not sure why.

The unease built to a head, and then the Liverpool "holiday" popped up …

After the shock of separation from our family, time passed in a blur of lessons, scrubbing floors, making beds and interminable inspections and tongue lashings. But then, on my 10th birthday, Mother visited with a gift – a silk scarf. She held me tight and wished me a happy birthday, saying: "Always remember, Anne, I love you more than I love life itself." Then, tearfully, she turned away. I watched her walk off, heels tip-tapping on the polished wooden floor, up the long corridor. She did not look back. Soon afterwards, I was summoned to the head's office. Miss Beard gently told me my mother "had gone to live with Jesus". She said: "She wants you to know that she is happy now, and loves you very much."

That she was dead was all I knew, and so, at the age of 10, I shut down. Don't show them anything was my credo. I insisted on telling Susan myself. I don't remember how, but somehow I did. We had no comprehension of where our world had gone – we were just two little girls clinging to each other for dear life.

But it appeared that our salvation was near at hand: Daddy was coming. My relief was enormous. Daddy would save us from this place.

He arrived, but he looked awkward, his smile lop-sided and unfamiliar. And why was the scolding cook with him?

Miss Beard said: "Anne, Susan – this is your new mother."

That was it. No more hugs or kisses. Don't show them anything. But I did. I wet myself. We packed our bags, two little girls in shock, and went home to Wales, where we found all traces of Mother had been removed from home. It was as though she had never existed. Even in family albums her head had been razored out. It was bizarre and upsetting to see her body, but no face.

On the few occasions I tried to talk to my father about it, he answered gruffly, telling me not to listen to any lies about us, that we should always look ahead in life, never back, and that when I was older I would understand. What I understood was that the subject, like so much with Daddy, was a closed book."Get on with life, Anne," he would say. And so we did. But Mummy lived on in my heart.

In December 1950, just five months after the death of my mother, flaxen-haired Paul was born. It was only much later, when I did the sums, that I realised that Edith's pregnancy with Paul had precipitated the disasters that had befallen us. My philandering father had got the cook pregnant and had panicked. Everything came to a messy head. Mother could not cope – a divorce and a pregnancy would have been terrible in those times. Susan and I were bundled out of the way until somehow things were sorted out. It wasn't for another five years, when I was 15, that I found out Mother had hanged herself when a chambermaid let it slip.

Where was my father in all this? He was there, focused on the business. He never intervened in any difficult situation between his daughters and his new wife; he seemed to blot out any discord or unhappiness by working hard. We loved him and he loved all of us, but there were no more hugs and kisses; all displays of affection had disappeared with my mother.

And Mother? What of her?

It wasn't until half a century later that we children finally laid her to rest.

In the summer of 2005 – 20 years after my father had died – Joan, my youngest sister, was on holiday in Snowdonia. While there, she visited the graveyard of Ynys Cynhauarn church just a mile from our childhood village, where our mother had been buried in an unmarked grave. Joan found herself suddenly angry and upset at the enormity of what had happened, and decided it was time to set the record straight.

Painstakingly, Joan researched parish records and talked to local officials, and was able to identify the spot where we believed our mother to have been buried. In 1950s Britain, suicide was illegal and deemed shameful, to be kept secret. Despite being a churchgoer, Mum was buried, without fuss, in unconsecrated ground.

Once Joan had the necessary details, we three sisters decided it was time to do something positive to confront and counteract the tragedy that had silently dogged us for 56 years. We had arranged for a headstone, and now the moment had come when we would relive those childhood emotions, numbed with shock and trampled on with such disregard so long ago – and, in so doing, heal our painful wounds.

The first sight of the headstone, a beautiful blue-grey slab of Welsh slate placed two weeks earlier, looked as though it had always been there. Then the tears came, softly healing the hurt of long ago. We had walked into the churchyard as three grieving middle-aged women. We walked out of it, arms linked, as three little sisters who had found redemption for their mother and resolution for themselves.

Always the Children by Anne Watts is published by Simon & Schuster, £12.99. To order a copy for £9.99 (including UK mainland p&p), go to theguardian.com/bookshop or call 0330 333 6846

• This article was amended on 5 July 2010. The original said that the

second world war ended in May 1945. This has been corrected.