The failure to deliver the letter is being probed by Royal Mail

An undelivered letter - which drew controversy due to a belief it had not been delivered because it was addressed in Irish - actually carried the wrong house number, it has emerged.

On Saturday, Royal Mail announced it had launched an investigation after it was accused by a Twitter user of not delivering a letter which had been addressed in Irish.

Piarais Mac Alastair took to Twitter after a letter he sent to Boucher Road in Belfast addressed in Irish was returned to him by Royal Mail.

A label attached to the letter said "the addressee was unknown" and there was "no such address".

One social media user described it as "shocking treatment of Irish speaker".

"They returned a letter with a clear address and post code on it saying the address did not exist," he said ending with #AchtAnois, the hashtag used by campaigners calling for an Irish language act.

Former Lord Mayor of Belfast Niall O'Donnghaile said it was an "ongoing problem" and has requested a meeting with "a representative of senior management in Belfast".

It has now emerged the letter, which was addressed to "UBE" at number 14 Falcon Road, did not carry a valid property number.

Royal Mail confirmed there was no number 14. There is, it appears, a 14b, and an Ulster Business Equipment is located at number 13.

After the initial complaint was made and investigation launched Royal Mail said the letter should have been translated and then delivered. It said staff would be reminded of the policy.

The carrier said it handles Irish language items on a daily basis, and "the overwhelming majority of these are delivered without any difficulty".

"Royal Mail also recognises the need to balance the requirements of customers for an efficient, value-for-money service, with the need to acknowledge our responsibilities as a major organisation operating in a society with diverse cultures. This has always been and remains our approach."

Belfast Telegraph