Stanley Johnson, father of British Prime Minister Boris Johnson, confirmed his plan to apply for French citizenship after Britain left the EU under the Brexit agreement.

"There is no doubt about being a French citizen. If I understand correctly I am French. My mother was born in France, my grandmother was French and my mother's grandfather was also French," said Stanley.

Stanley, 80, was one of the first civil servants appointed to Brussels after Britain joined the European Union (EU) in 1973. He worked for the European Commission and was a member of the European Parliament.

Initially, he campaigned against Britain's departure from the EU but changed his mind, a year after Britain voted to leave the alliance in 2016.

"I will always be European, that's for sure," he said in today's interview.

His plan to apply for a French passport was revealed by his daughter Rachel in a book published in March. Rachel said that if her father accepted French citizenship, she would also want to become French.

Prime Minister Boris Johnson ended Britain's 47-year membership in the EU with a Brexit deal reached last week.