The Saudi Arabian authorities are refusing to reveal what action was taken against a diplomat suspected of sexually assaulting a child in London.
The UK would like to know what happened to the man
The man was arrested at the end of July last year but was released after claiming diplomatic immunity.
The Saudis say he will not be able to return to the UK, but have offered no information as to his fate.
The Foreign Office has refused to hand over papers on the case, despite a BBC freedom of information request.
The alleged assault against the 11-year-old girl generated anger in the newspapers when the Saudis refused a request by the British to waive the man's diplomatic immunity.
This left police unable to even question the man about the allegations.
There were calls at the time from then MP Barbara Roche and lawyers for the issue of diplomatic immunity to be reviewed.
The Saudis have steadfastly refused to comment on the case.
It was understood that the man would be dealt with by the Saudi justice system on his return. But the outcome of the Saudis' investigations remains unknown.
Responding to a freedom of information act request from the BBC News website, the Foreign Office has refused to release documents detailing its communications with the kingdom's mission at the time of the arrest.
It is currently reviewing this decision.
Neither the Foreign Office nor the Saudi Embassy have revealed the identity of the man.
The Saudis have given an assurance that the man would not be able to return to the UK, although how this would be enforced has not been revealed.
The Foreign Office says it is very confident there is no possibility of the man entering the UK again.
Prince Turki complained of a trial by media at the time
Nikki Kerr, of child protection charity Kidscape, said the use of diplomacy and the Saudis' refusal to reveal the fate of the man raised serious issues.
"Every time somebody claims diplomatic immunity when they don't want to answer allegations is worrying.
"The fact they have promised he won't come back into the country doesn't matter. I don't know how much we can trust any country.
"I don't see why they can't name him. We really want to know what he is doing now and where he is."