The Duchess of York has paid a glowing tribute to Prince Andrew, who strongly denies claims of having sex with an underage girl.

Speaking for the first time since the allegations against the Duke of York surfaced, Sarah Ferguson said her former husband was "the best man in the world".

The Duke flew home on a private jet from a ski resort in Verbier, Switzerland, following the claims, which were made in court papers in the US.

The Duchess (55) who had been on holiday with the Duke and the couple's daughter, Princess Eugenie, remained in Verbier, where she spoke to reporters as she headed off for a mountain walk.

Asked if she was sticking by the Duke, she replied: "The York family is a tight unit. We've always been a tight unit.

"He is the greatest man there is. It was the finest moment of my life in 1986 when I married him. He is a great man, the best in the world."

The Duke (54) reportedly spent the day at Royal Lodge, the home in Windsor Great Park he shares with the Duchess.

Buckingham Palace has in recent days issued two denials over the woman's claims.

It has "emphatically denied" the Duke had sexual contact with the woman, who has been named in reports as Virginia Roberts.

A Buckingham Palace spokesman insisted "any suggestion of impropriety with underage minors" was "categorically untrue".

The woman's father, Sky Roberts, claimed in an interview with the Daily Mail that his daughter met the Queen during a visit to London.

However, a palace spokesman insisted: "There is nothing to suggest the claim is true. We have no record of such a meeting."

Scotland Yard has confirmed it has not received a complaint relating to the case, but added it would investigate if an allegation was made.

Two Sunday newspapers have published details of interviews with the woman, who reportedly named Prince Andrew in US court documents.

Her claim is part of a lawsuit in connection with American billionaire and convicted paedophile Jeffrey Epstein - a former friend of the Duke.

Andrew was photographed with Epstein in New York two years after his release from prison in 2009, and has faced criticism over their friendship.

In an interview in 2011 he denied any sexual contact with any of the young women connected to the banker.

The woman claims that between 1999 and 2002 she "was forced to have sexual relations with this prince when she was a minor" in London, New York and on a private Caribbean island owned by Epstein.

She is believed to have been 17 at the time - underage in US law.