My father Vasile lives a quiet life in the Romanian countryside. He's 63 and grows vegetables on his land. When he arrived in London last Christmas, he had only visited once before, two years ago for my wedding. He has no knowledge of London and he speaks no English.

On my birthday, the two of us were heading to the Russian Orthodox church in South Kensington before visiting the nearby museums. My wife, Olimpia, drove us to Colliers Wood station, where we took the Northern line and changed at Stockwell for the Victoria line. It was 10am. We stood on the busy platform, my father behind me.

The train arrived, I stepped inside and the doors closed instantly. I turned round to see my father still on the platform. I looked out of the window and gestured at him to stay where he was. I thought I would see him again within five minutes. I got off at the next station and took a train back to collect him. But he wasn't there. For the next hour I sat on platforms and wandered around Stockwell station looking for him.

As time ticked on, I began to worry. I decided to take the train home to Sutton. When I found the house empty, I rang the police. Olimpia and I then called everyone we knew and the Romanian embassy. We searched everywhere in Sutton, and my sister Alina, who lives in London, tried to find him in Stockwell, but no luck. He had picked up a spare iPhone from our house, thinking he could use it, but it didn't have a sim card in it.

The first night was a living nightmare. It was like a role reversal in which we were the parents and our child hadn't come home. We called the police every hour, but they had nothing to tell us. They called hospitals, but again nothing. It was cold and we had no idea where he was sleeping. As Dad had only £20 on him and no bank cards, I knew he couldn't have checked into a hotel.

Two more worrying days passed. With the help of friends, we looked all over the area, driving around and on foot. Newspapers published photos of him and ran appeals for information. On the fourth day there was still no sign. We tried to stay optimistic, and that evening our relatives and friends gathered to pray together. And then the call came from a police station in west London to say they had found him far away in west London.

When we became separated, my father had misunderstood my gestures and took the following train to the next station – where I had been minutes before. He waited a while and then decided to make his own way home. But he went in the wrong direction and when he came out of the tube he was lost. He found two police officers and tried to explain he needed help, but they didn't understand him. On his first night on the streets, he kept walking so he didn't get stiff. Even though he is retired, Dad still walks very far, and he is used to terrible winters in Romania. On the second day, he found a betting shop where they let him sit inside until 10pm, when it shut. Then he went back to walking the streets and huddling in bus stops. Mindful of the fact he didn't have much money, Dad survived on sandwiches and milk from corner shops.

Vasile Belea. Photograph: PA WIRE

His recollection is quite blurry. On the third evening, he found an Indian restaurant where they offered him food and kept him warm. Because of their kindness, he returned there on the fourth evening, and happened to pick up a newspaper that had his photo inside. Dad ran up to the waiter, pointed at the article, and the waiter called the police.

My father was found 10 miles from where I had lost him in Stockwell. When we picked him up from the police station, he was tired but well. He said, "I'm OK, everything is OK." He still had £3 on him.

Throughout this ordeal, my father never despaired or panicked. He loves London and said everyone was very kind to him. People say to us those four days must have been awful, and they were. But whenever I was feeling low, my wife would pick me back up, and vice versa. It was teamwork in positive thinking.

We want to thank the Indian restaurant, but we may never know which one it is.

• As told to Anna Dubuis

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