A T-shirt with a rude slogan in Welsh about Englishmen made an unexpected appearance on BBC Two's Newsnight.
Martin Davies' T-shirt was spotted by eagle-eyed Newsnight viewers
It was worn by an interviewee in a film revealing that a version of the Welsh national anthem had not been played by guitar legend Jimi Hendrix.
Messages left on Newsnight's website said the programme had been "had".
But while host Jeremy Paxman did not offer a translation - or an apology - he suggested that non-Welsh speakers could look up the meaning.
The T-shirt made its appearance in the Newsnight report, which went out on the eve of St David's Day, 1 March.
The flagship news programme has been following the tale of the guitar version of Hen Wlad Fy Nhadau.
Speculation had been growing that it was an undiscovered piece of work by Hendrix, who died in 1970 and is regarded by many as one of the greatest rock guitarists.
However, the owner of the tape, Martin Davies, told the programme that while he "could be accused of hoaxing," he had just been having "a bit of fun".
It turned out that Davies had got his musician friend John Ellis to play the song in the style of Hendrix, and then put it on his website.
But while that controversy was put to bed, another began with the appearance of the T-shirt worn by Mr Davies, who was described by the programme as either a "visionary or Taff time-waster".
At the end of the St David's Day programme, Paxman said "sharp-eyed viewers" had "spotted this Welshman in last night's programme."
"Yes, our producer Meirion Jones did realise what was written in Welsh on the man's T-shirt, but somehow he failed to tell Steve Smith, our truly English correspondent," he said.
"I'm afraid if you don't speak Welsh you'll just have to look it up," he added, before signing off with a cheery "Happy St David's Day."
Several people on Newsnight's website also pointed it out, although one wrote: "The story was less interesting than the T-shirt."
"Come on BBC, someone should have got Huw Edwards to translate the T-shirt."