LONDON — In the flood of news about Britain’s withdrawal from the European Union, a few seconds of black-and-white film broadcast on the BBC stood out on Wednesday.

As an anchor ended an evening news program by saying, “Theresa May says she intends to go back to Brussels to renegotiate her Brexit deal,” the screen showed grainy images of World War II planes that appeared to be Spitfires.

The odd pairing caught the eye of many viewers, who shared the video clip on social media.

“For those wondering — simple human error at end of #BBCNewsSix,” Paul Royall, the program’s editor, wrote on Twitter. “If and when it happens pretty certain PM not travelling to Brussels like this.”

Mr. Royall said the footage had been shown earlier on in the program to tease a story about a museum that opened at the former Biggin Hill airfield, the busiest during the Battle of Britain.