Eighty years ago, on the night of 9 November 1938, tens of thousands of German Jews were arrested in a nationwide pogrom that became known as Kristallnacht, the Night of Broken Glass, because of the thousands of windows that were shattered in Jewish-owned shops, businesses, homes and synagogues.

My father and grandfather went into hiding the following day, to escape arrest. Five months later, in April 1939, my father left Germany and sought refuge in Britain. His parents escaped a year later and fled to Portugal.

Last week my son, daughter, brother and I went to the German embassy in London to pick up our certificates of German naturalisation. We are now German citizens. (We remain, of course, UK citizens as well, and I have no intention of ever using a German passport.)

My father died last year at the age of 98 but he knew that we had applied for naturalisation, and understood our reasons. He could have applied as well but saw little point. Having served in a top-secret unit of British military intelligence during the second world war, and having lived in the UK all his adult life, he was every inch a proud and loyal British citizen.

He lost his German citizenship in 1941, when the Nazis introduced a decree that stripped any German Jew living outside Germany of their citizenship. However, once the Nazis had been defeated, new legislation enabled any former German citizens who had been deprived of it on political, racial, or religious grounds, as well as their descendants, to apply to have citizenship restored. Hence our trip to the embassy.

Facebook Twitter Pinterest Fritz Lustig during his time in military intelligence. Photograph: Robin Lustig

But if I don’t intend to make use of it, why did I bother? First, because after the Brexit referendum it was important to show that I retained a deep attachment to my European identity. I have lived and worked in France, Spain and Italy, and I resented Theresa May’s saying to the Conservative party conference two years ago: “If you believe you’re a citizen of the world, you’re a citizen of nowhere.” Second, because one day my son or daughter might want to live and work in the EU. Until the Brexit referendum they had always assumed that they would have that right. After March, however, they are unlikely to retain it if they are no longer citizens of an EU member state. So for them, it is entirely possible that German citizenship could be of real benefit.

But third, how better to demonstrate – for my own satisfaction if not for anyone else’s – that the Nazis’ genocidal project utterly and totally failed. If postwar Germany, which has so impressively confronted the full horror of its own history, enables us to undo at least a tiny part of the immense harm done to our forebears, then it would surely be ungenerous to refuse the offer of an outstretched hand.

As it happens, my family marks another anniversary this month. In November 1941, 77 years ago, my maternal grandmother, Ilse Cohn, was deported to Lithuania from her hometown of Breslau (now Wrocław in Poland), and murdered by a Nazi death squad in Kaunas. My mother, Ilse’s only child, had escaped to England barely a month before the outbreak of war, but Ilse’s application to come with her had been refused because, at the age of 41, she was considered too old.

I have visited Kaunas, and I have stood at the edge of the killing field where my grandmother and 2,000 other Jews, including 150 children, were murdered on the same day. The men who shot them were probably Lithuanian, not German – and the commander of the death squad, SS colonel Karl Jäger, was Swiss. (He escaped arrest at the end of the war and lived quietly as a farm worker until he was discovered in 1959. He killed himself while awaiting trial.)

Both my parents always insisted that they felt a deep sense of gratitude to Britain for having taken them in when their lives were in danger. In 1989, on the 50th anniversary of their arrival here, they threw a “thank you” party for all their friends, and my father’s speech moved several guests to tears. In his memoir he wrote: “I call Great Britain my ‘home country’, as I feel at home here, and I am glad this is where I lived my life, rather than anywhere else.”

I feel the same. I could have chosen to live in many different countries, but in all my travels during a long career as a journalist and broadcaster – nearly 90 countries and still counting – I have never found anywhere I would rather call home. So in no sense do I regard my newly-acquired German citizenship as a replacement for my British identity. It is an addition, and an explicit repudiation of the idea that one’s identity must be rigidly confined to national boundaries.

I was born and brought up in Britain, as a British citizen. I am not blind to its faults, nor do I deny its many virtues. But ask me how I identify myself and I will reply with a long list: I’m British, I’m European, I’m a Londoner, I’m a male, I’m a journalist, I’m a father and a husband.

Less than two weeks before I acquired my German citizenship, a gunman in Pittsburgh murdered 11 Jews in a synagogue. The following day I received an email from a woman I met four years ago on a visit to Germany with my father.

She wrote from Magdeburg, an ancient university town where some of my father’s family had lived, and from where three of his cousins were deported to Theresienstadt and Auschwitz. This is what she said: “It is 80 years since the synagogues were attacked here, and we all know that it was the prelude to millions of murders. Since 1945, and every year since then, when we remember what happened, we realise how important it is to fight back from the beginning.”

Robin Lustig is a journalist and broadcaster. He presented The World Tonight on BBC Radio 4 between 1989 and 2012.