She’s still alive,” I said to my brother. We’d begun to talk about Mum again, as we did from time to time. It was July and I’d just found her house on the Land Registry, still registered in her name. We needed to know or, rather, we needed an end to the not knowing. I emailed her local council, as I’d done several times before, to ask if she appeared on its records.

We hadn’t seen Mum for more than 35 years, since our father left her for someone else. Shortly afterwards, Mum cut herself off from both my brother and me; it was if she was angry with us, as if we were equally to blame for his leaving. Coming to terms with this was, needless to say, difficult, but in recent years I’ve arrived at some kind of peace. I’ve forgiven Mum - and myself – for not knowing better how to deal with her silence.

Assessing my childhood, measuring happiness against unhappiness, might remain problematic, though there’s little to tell me that it was unusually difficult. Through my teenage years though, it was apparent that our parents were becoming increasingly unhappy. Every house we lived in was in some way wrong; Dad had to move for work and every few years we moved again.

Karen’s mother, Renee.

Mum changed from being a self-reliant young woman who had served in the Land Army and worked in postwar Liverpool as a store detective, to someone dogged by bad health and depression. In the 1960s, she had a hysterectomy and her emotional health deteriorated. Frequently I came home from school to drawn curtains and Mum curled up in bed.

She was prescribed anti-depressants – the type we know now are hugely problematic.

Another move. This time away from Cumbria where we’d grown up, back to Merseyside. This was to be the one that gave Mum back her happiness; taking her home to the Wirral and proximity to the Liverpool she still missed. Her sister and family were there too. But the forecasted good times did not return. It was inevitable that they could not.

While I don’t blame Dad for leaving, it soon became apparent that I was part of his master plan for extricating himself from the marriage. One of the first things Dad said to me after Mum found his incriminating letter was to ask if it was it was too soon for me to begin looking for somewhere for mum to live – near me. I felt pigeonholed; the dutiful daughter – the female as carer. Dad simply expected that I would take on responsibility for mum.

In 1981 I was 23, living in a one-bedroomed flat and working in a demanding job with anti-social shifts. I wanted to get on with my life and was planning to move from Cumbria to Edinburgh. When Dad moved out, Mum stayed with me and that week it seemed that we became closer than ever.

Karen Lloyd with her mother and brother.

We talked about things we had never had before. I thought I could see a way to make the future work for us both. We visited a garden in sunshine, a cafe in Ambleside; I believed that things were going to be OK. But I came to the only conclusion I could. I couldn’t take full responsibility for Mum alone. If she could learn to be a little bit independent then we could plan. This seemed reasonable.

I suggested that she take time to think about what she really wanted to do, rather than what Dad imagined she should. But the day Mum was due to return to the Wirral, she stopped speaking. She remained silent, refusing to look at me even, tears streaming down my face as the train pulled away from the station.

That was the last time I saw her.

After this, communication soon broke down. My letters were returned unopened, the phone put down and when we went to visit mum wouldn’t open the door. The coming months and years were so difficult, trying to encourage her to come back to me, asking her forgiveness for me not doing the right thing and trying to find a way forward. But the silence continued.

In addition, I didn’t see my father for 18 months as I found the prospect just too difficult. He had written telling me that I should understand that his responsibilities lay elsewhere now – with his new partner and family.

Living alone, my feelings around this time were of grief, confusion and depression; good friends provided invaluable support. I took to walking at dusk, looking in at windows to see families being normal, always unable to come to terms with the loss.

In my 30s, I met and married Steve and very soon our first son was born. I gave up work and loved being with my son full-time. I wrote to tell Mum the news of her first grandson’s arrival. I kept writing and sending photographs; surely this would be the key? But the silence grew.

Out of the blue, a parcel arrived. Mum’s handwriting was unmistakeable. Inside was a selection of family photographs and a coloured drawing of animals she’d done for my son. He asked if he could meet his gran, so we sat down to write her a letter together.

The reply, when it came, was, “Don’t use the boy as a pawn in the game.”

The reply to my email to my mother’s local council arrived a week later: “I am sorry to tell you that your mother passed away in January.”

I took in the announcement. The quiet shock; the silence of the intervening years suddenly broken. I phoned my brother; he was in a supermarket car-park. We could not cushion the blow. But perhaps now we could piece together the unknown part of her life.

We drove to her house. Would it be rented out? For sale?

Mum’s garden was overgrown, shrubs penetrating the fencing and piles of accumulated post behind the glass door. Although the house seemed empty, we knocked on the door, not knowing if anyone might be there. Then we knocked on a neighbour’s door and haltingly told the lady who answered who we were. She invited us in and we exchanged stories. A little later, she passed me the telephone and I was speaking to the woman who had cared for Mum in the last years of her life. She had died, aged 91, after a fall at home.

A few days later, my brother and I went to meet the woman who had looked after our mother. She was perhaps in her 70s and had gathered her family around her; also the neighbour who put us in touch. I felt like an imposter – how to explain that I was not the one who had closed the door all those years before?

Karen and both her parents.

They must have been suspicious of us. For a while we skirted around each other but eventually were able to begin the necessary exchange and gathering of so much missing information. They knew of our existence, but that was all. They told us that Mum had friends, had not been isolated. Then the darker stories detailing mum’s stranger behaviour began. Of silent phone calls to neighbours who might have annoyed her in some unwitting way. I remember feeling an almost overwhelming sense of relief, though, that it had not been me alone who had failed her, not been good enough.

I, too, knew about silent phone calls. Once or twice a year, usually close to a birthday (mine or hers), the phone rang, but there would be only silence. (This was before cold-calling took off). Once I said, “Mum, if it’s you, it’s OK to talk to me.”

That was the last call.

“Do you think your mother might have had a personality disorder?” the carer’s son asked.

We only began to think about this in recent times, of how some underlying difference might perhaps have been the key to her behaviour – the black or white responses, an inability to empathise – even allowing for the awful effects of prescription drugs.

When I phoned Mum’s brother (from whom she had also alienated herself) to tell him of her death, he told me that mum had always been extremely difficult to be close to, even as a small girl. He said that she was beautiful (so beautiful,) but always emotionally distant. The picture was becoming clearer.

As we left the house, Mum’s carer hugged me. It was the closest I felt I’d been to my mother since I was 23. It was a strange, emotional moment.

By the time of the meeting, I had lived longer without any relationship with Mum than I had had with her. There was a huge sense of relief in knowing that she had been cared for, come what may, and that she had not become completely isolated. For this I am grateful.

The thing that troubles me still, though, is this idea of shutting out your children. I wondered just what maintaining her silence with us throughout all those years had been like for her. Even if we had failed her, I can only think that the loss of one’s children would result in more pain than resolution. To shut them out, to deny their existence, is a loss I couldn’t begin to countenance.

The Gathering Tide: A Journey Around the Edgelands of Morecambe Bay by Karen Lloyd is published by Saraband, £12.99. To order a copy for £10.39, go to bookshop.theguardian.com or call 0330 333 6846