A whistleblower who took part in an RTÉ Prime Time programme, and who was allegedly afterwards defamed on social media, has asked the High Court to help direct the unmasking of the anonymous user.

Stephen Walsh, of Crinken Glen, Shankill, Co Dublin, was today granted an order directing Twitter to provide information that may lead to identifying the author of the tweet.

Barrister Daniel Fennelly said during a late sitting of the High Court tonight that Mr Walsh had been subject to alleged defamatory messages on Twitter.

Mr Fennelly told Mr Justice Colm Mac Eochaidh that Mr Walsh was seeking information from Twitter International Company to help identify the anonymous user.

Counsel said the matter was urgent as there was a concern that the computer or phone, used to send the alleged defamatory messages, might be disposed of.

The programme, which was broadcast on 16 July last, was investigating procurement practices in Irish hospitals.

Reporting restrictions were initially applied to the matter, but following an application by solicitor Hugh Hannigan, for the Sunday Times, the judge ordered that Twitter International Company give today the name of the anonymous user.

Following a brief adjournment, Mr Fennelly said Twitter had not given the user's name, but had provided details including an email address.

Judge Mac Eochaidh, who then lifted the reporting restrictions, made an injunction prohibiting any person/persons having access to the anonymous user's Twitter account from destroying the computer/phone from which the tweets were sent.

The court heard that defamation proceedings will be issued against the anonymous user.