For the Welsh for "others safe", the test message read "eraill yn Vogel" instead of "eraill yn ddiogel".

Vogel has no meaning in Welsh, as there is no letter V in the alphabet. But it is a ski resort and German for bird.

Deputy Prime Minister Oliver Dowden insisted the "essence of the message remained unchanged".

The message appeared on the home screens of mobile phones and tablets at 15:00 BST, accompanied by a loud siren-like sound lasting about 10 seconds.

He told MPs: "An online system made a small autocorrect, rendering one word in the Welsh test message incorrect."

He also said anyone travelling between Wales and England on Sunday would have received two alerts.

This, he added, would be addressed in a "lessons learned" exercise.

Mr Dowden has said one in five compatible mobiles did not get the alert, with the Three network having a problem supporting multiple messages, which meant some people did not get it.

Mr Dowden called the test successful, saying it was, "the largest simultaneous public message in UK history".

He said there were "no security or public safety issues" and no events were disrupted.

"The system is now fully operable," he said, adding that further tests were possible.