Award-winning, Belfast-born playwright Marie Jones was declared by a High Court judge in London yesterday to be the sole author of her hit play Stones In His Pockets.
Mr Justice Park rejected a claim by theatre director Pam Brighton that she should be credited as joint author of the comedy, which he said had become "a big hit and a major commercial success".
But the judge said Ms Brighton had copyright in a "draft opening script" she had provided in notes to Ms Jones before the play was written in 1996.
He ruled that Marie Jones was the sole owner of the copyright in the 1996 script of the play and of her later 1999 version of the play.
He added: "However, for the future, Ms Brighton, through her copyright in the draft opening script of the play, is a person whose consent is needed for new contracts by Ms Jones to exploit the copyright of the 1999 version."
Marie Jones had contested the claim by Belfast-based Pam Brighton for damages or an account of profits for alleged infringement of copyright over what has become one of Ireland's most successful stage plays, performed in 20 countries in 16 languages.
Ms Jones (52), extensively rewrote the play in 1999 and has gone on to win huge acclaim. The play scooped a number of awards.
The judge went to see the play, which is about two extras working on a Hollywood film being shot in Co Kerry, at London's New Ambassadors Theatre during the courtroom wrangle.
Marie Jones and Pam Brighton first met in 1983 through their work in the theatre.
Ms Brighton was not in court yesterday but a statement issued by her solicitor said she had "brought the proceedings to establish that this award-winning play utilised, to a significant extent, her copyright material in the 'notes' which she provided to Marie Jones before the play was written - and that is exactly what the judgment today has established".