A sign language interpreter at the Nelson Mandela memorial has been called a 'fake' [REUTERS]

The unidentified man stood next to the world’s most powerful leaders but instead of translating their speeches for the deaf community has been accused of signing “gibberish.”

Today questions have been raised as to how he was chosen and then given access to the likes of US President Barack Obama and South Africa’s leader Jacob Zuma. 

"He was basically gesturing. He didn't follow any of the grammatical rules and structure of the language. He just invented his signs as he went along," said Delphin Hlungwane, an official sign language interpreter at DeafSA. 

"There was zero percent accuracy. He couldn't even get the basics right. He couldn't even say 'thank you'," she said.

Bruno Druchen, DeafSA’s national director, agreed saying the man’s hand signs had “no meaning” and the signs he used would not be recognised by the signing community.  

Mr Druchen has demanded an urgent meeting with the ruling African National Congress (ANC) about the interpreter he called a "fake".

The interpreter (far right in each picture) with the Chief Rabbi of South Africa Warren Goldstein [REUTERS]

He didn't follow any of the grammatical rules and structure of the language. He just invented his signs as he went along

Delphin Hlungwane from DeafSA

He said: "We want to make a statement that this is a warning to other sign language interpreters who are fake and go about interpreting. 

"I am hoping the South African government will take notice of this."  

Ingrid Parkin, principal of Johannesburg's St. Vincent School for the Deaf, said she received complaints as far as China and Canada about the Mandela memorial interpreter.

The complaints said the man looked like he was "signing gibberish" and he used no facial expressions to convey emotions which is a key part of sign language interpretation.

Ms Parkin added: "This man himself knows he cannot sign and he had the guts to stand on an international stage and do that."

South African Presidency Minister Collins Chabane said the Government is currently in the process of investigating the matter. A hunt has also been launched for the unknown signer.

The interpreter (left) with US President Barack Obama on stage at the Mandela memorial [AP]

Mr Druchen added the man appeared an event last year attended by President Jacob Zuma and at the time they were handed a complaint by a deaf audience member.

The Deaf Federation filed a formal complaint to the ANC but did not receive a response and are preparing to file a fresh complaint about the latest incident.

In their first complaint the Deaf Federation said qualified sign language interpreters need five years of training.

Ms Parkin explained that bogus sign language interpreters are a problem in South Africa as people who hire them often do not know sign language.

She said: "They advertise themselves as interpreters because they know 10 signs and they can make some quick money.

"It is plain and simple abuse of the deaf community, they are taking advantage of the deaf community to make money."   

As well as the national embarrassment, questions have been raised as to how he was employed and given an official security pass.  

In an apparent security failure, police also did not search the first wave of crowds arriving at the stadium.