The UK's top intelligence agency has apologized after social media users spied it using an offensive word in an online quiz.
GCHQ is famed for its code-breaking prowess, playing a key role in uncovering Nazi messages during the Second World War.
However, the security body appeared to have suffered a brief lapse in concentration on Tuesday when it included a swear word in the answer to one of its regular Twitter puzzles.
The unfortunate post underlined the fourth letter in the names of the planets Mercury, Venus, Uranus and Neptune.
A GCHQ spokesman:
“We apologize for any offense inadvertently caused by this morning's post. We deleted it as soon as we became aware of the issue."
The tweet was deleted after being online for less than 20 minutes.
A different version, minus the swearing, was later posted online, instead underlining the fourth letter in the names of all eight planets in the Earth's solar system.
Twitter users were quick to mock the error.
Lesson learned, we hope!