The BBC has apologised for accidently naming a South African civil servant with the name “gay marriage” in a TV news report about a diplomatic conference.

The blunder happened earlier this week on BBC World News, the corporation’s international channel.

Instead of “Rufus Lekala”, an on-screen caption named the interviewee as “Gay Marriage”, presumably intended for an item about equal marriage and the US Supreme Court.

Mr Lekala is chief harbourmaster at Transnet, South Africa’s national transport company.

Transnet subsequently contacted the BBC for an explanation after a screen grab of the caption began circulating on social media.

Transnet spokeswoman Lunga Ngcobo told South Africa’s Times newspaper: “We understood that it was a mistake. But we have asked [the] BBC to explain how this happened. We want them to get the facts correct. We think it’s a similar mistake that often happens [with] other media houses. But they apologised after [being] alerted about the error.”

In response, a BBC spokeswoman said: “During transmission of a recorded report on shipping in South Africa, a topline aston strap was erroneously transposed by our MosART automation system over a voiceclip from Captain Rufus Lekale from Transnet when the item played out in our 0800GMT news bulletin.

“We apologise to Captain Lekale for any embarrassment this technical error may have caused.”

South Africa remains the only country in Africa to have legalised same-sex marriage.