Emma Thompson fights plagiarism claim over new screenplay

Emma Thompson is embroiled in a legal row that is threatening her new film about the love triangle involving 19th-century art critic John Ruskin.

The Oscar-winning British actress and screenwriter has gone to the federal court in New York to contest claims that her screenplay, Effie, plagiarises The Countess, an earlier play on the subject by US playwright Gregory Murphy.

Both play and film centre on Ruskin's marriage to the much younger Effie Gray which was never consummated.

Gray eventually fell in love with Pre-Raphaelite artist John Everett Millais, for whom she modelled, and petitioned for a marriage annulment, scandalising Victorian society. Thompson's film is set to star Atonement actress Saoirse Ronan as Effie with Orlando Bloom as Millais and Thompson's husband, Greg Wise, as Ruskin.

It is understood from reports in America that Murphy's representatives have raised concerns about the film script, and that Thompson is seeking a "declamatory judgment" against him.

Part of the legal submission to the court states: "In order to close financing to produce a motion picture based on Effie, [the plaintiff] must be able to demonstrate that there is no validity to Mr Murphy's claim of infringement." The play had a long run on Broadway in 1999 and came to London in 2005, but Thompson is said not to have seen or read the piece.