For years, Andre Geim was known to the world as a Nobel Prize-winning Dutch physicist, which suited both him and the Dutch just fine. He is still a Nobel Prize-winning physicist, but now, according to the government of the Netherlands, he is no longer Dutch.

He is, he said in a show of considerable understatement, “extremely annoyed.”

Thirteen years ago, Mr. Geim took British citizenship to accept a knighthood, and until recently he had no inkling that it would cause a problem. He said he was informed that he was no longer a Dutch citizen and must hand his passport over at the embassy in London or face consequences from Interpol, because the Netherlands sharply restricts dual citizenship.

“Personally, I consider myself a Dutch-British Nobel Prize winner (in this order),” he said in an email. “The history and my time living and working in the Netherlands are very close to my heart.”

The decision to revoke his citizenship, he added, “is just so sad and odd.”

Mr. Geim was born in 1958 in Russia to parents of German descent. He adopted Dutch citizenship in the 1990s while at Radboud University in Nijmegen, the Netherlands, working on what would prove to be groundbreaking physics.

In 2010, he and his colleague Konstantin Novoselov — who were by then working in England — won the Nobel Prize in Physics for their experiments creating graphene, the world’s thinnest and strongest material.