AN American builder's attempt to take an aristocratic title off an Oxfordshire man failed today.

Californian construction boss Paul Fitzgerald claimed he was the rightful holder of the historic title of Duke of Leinster, held by Oxfordshire landscape gardener Maurice FitzGerald and granted by George III in 1766.

The Lord Chancellor, Lord Falconer, said that the American's claim - which had been backed by years of research and DNA evidence - was not "made out".

The title will remain with Mr FitzGerald, 59, who lives at Oakley Park, Frilford Heath. His father inherited the title in 1976.

The 40-year-old pretender, from San Francisco, claimed the 5th Duke's middle son, Desmond, had not died in the First World War, as previously thought.

He said Desmond had in fact emigrated to Canada, where he established a new line of the family, and was entitled to inherit when his elder brother died in 1922.

A spokesman for the Department for Constitutional Affairs said that following careful consideration of the competing claims to the Dukedom and Viscountcy of Leinster, the Lord Chancellor was satisfied Maurice FitzGerald was the rightful claimant and his name had been added to the Roll of the Peerage in accordance with a Royal Warrant dated June 1, 2004.

She added: "The Secretary of State is not satisfied that the claim of Paul Maurice Fitzgerald has been made out."

Paul Fitzgerald's 81-year-old great-aunt reportedly spent 30 years and more than £1.3m gathering evidence to back up his claim. The dossier included DNA samples from her late father's exhumed body and sworn affidavits from former family servants.