Thomas Harding was so appalled by the Brexit vote that he has applied for a German passport – a surprising decision given his heritage

At 9.59am on 24 June 2016, just hours after the BBC announced that the UK had voted to leave the EU, I sent an email to the German embassy in London: “I would like an appointment so I can apply for a restored citizenship.”

To those who know me, this might come as a little surprise.

All my life I have found it hard to forgive the Germans. In 1934, my grandmother was thrown out of Heidelberg University simply because she was a Jew. My great-grandfather was forced to shut down his medical practice a few months later. Two years after that, my grandmother, her parents and siblings had to flee Nazi Germany, abandoning their apartment in Berlin and lake house just outside, and became refugees in England. In 1943 and 1944, five of my grandfather’s uncles and aunts were murdered in Auschwitz and Riga.

Growing up, we didn’t buy German washing machines or cars. We holidayed in Paris, Barcelona and Rome, but never Berlin or Frankfurt. When I was 20 and 30, I visited Germany and when I walked down the streets I never felt comfortable. When I saw someone above a certain age, I wondered “what was your role in the persecution of the Jews?”

Then, in my 40s I wrote Hanns and Rudolf, about my grandmother’s brother Hanns who tracked down and arrested the Kommandant of Auschwitz. At talks I was often asked what today’s Germany was like and I was never quite sure how to answer. At one event, an elderly Holocaust survivor asked if I often visited Germany for my research. When I said yes, he asked, “And do you shake their hands?” I replied, yes, of course; shocked, though I understood what he meant. So why would I now apply to become a German citizen? Three things have happened.

First, I have become familiar with scores of ordinary Germans. Since July 2013, I have been working with the residents of a small village outside of Berlin to save our family’s 1930s lake house from destruction. In public meetings, while clearing up the garden, over Kaffee und Kuchen, I found them not only warm, open-hearted and hard-working but also, dare I say it, funny. I no longer fear attack every time I stroll down the Kurfürstendamm or ride the U-Bahn.

Second, I have been inspired by Angela Merkel and her government’s decision to take in more than a million refugees from Syria and other conflict zones. While this poses startling political risks, Germany’s audacious immigration policy displays considerable grace and courage, in sharp relief to the country’s terrible past. I am also grateful to the German government, as immigrants include nine of my sister’s nieces and nephews who have just arrived from Damascus (she married a Syrian Kurd 25 years ago).

Then, of course, there was the Brexit vote. I felt sick when I heard that the leave vote had won the referendum. I was about to be stripped of my EU passport, no longer would I have the right to work and live in 27 other European countries. This felt like a real loss. If the UK was going to leave, how could I remain? Then I remembered that I had a right to apply for German citizenship.

Why? Because four years after the end of the second world war, the West German government enacted its first constitution, known as the Basic Law, including Article 116 paragraph 2 which stated, “Former German citizens who between 30 January 1933 and 8 May 1945 were deprived of their citizenship on political, racial, or religious grounds, and their descendants, shall on application have their citizenship restored.”

Early in the afternoon of the Brexit result, I received a phone call from a Berlin friend. He said that the German federal government had agreed to contribute €140,000 towards the restoration of the lake house, towards its transformation into a centre of education and reconciliation. So, at the very moment that the UK was pulling away from Europe, Germany was working to bring Europeans together.

When I called a Berlin lawyer on the Monday after the referendum, she wasn’t surprised by my request. “We have had many calls like yours since Friday,” she said. My application might take longer than usual, she added, as the German government hasn’t hired any extra officials to process applications. But it should be a formality.

“Hope for the best and prepare for the worst,” I tell my wife. I will keep my UK passport and have no plans to leave the country any time soon. But it’s nice to have options.

• The House by the Lake by Thomas Harding is published in paperback by Penguin Random House.

@thomasharding