In a knee length dress and white jacket the Duchess of York looked the image of respectability. Until the wind began that is.

As she walked across the polo field Sarah Ferguson's flimsy dress blew up, exposing her legs to the watching crowds.

Her quick reactions were all that stopped an embarrassing moment as she reached down to hold the skirt firmly in position.

Thigh-high: As Fergie picks her way across the mud she reveals her leg

The black and white wrap dress, decorated with musical notes, then slid to one side as the Duchess gingerly picked her way across a patch of mud in her white flip flops.

But the former wife of Prince Andrew didn't seem put out by her wardrobe malfunction.

Instead the 48-year-old was all smiles as she joined daughters Beatrice and Eugenie in cheering on the teams at the final of the Gold Cup polo match at the Santa Maria Polo Club in Sotogrande, Spain.

Oops: As her flimsy skirt flies up Sarah Ferguson only just avoids revealing all

The trio are enjoying a rare family holiday together to celebrate Princess Eugenie's brilliant A'level results and Princess Beatrice's recent 20th birthday.

The break may be the last time the three are together for a while. After receiving two As and a B at A' level 18-year-old Eugenie is expected to soon head off on her gap year abroad.

Meanwhile, Bea is gearing up to start a degree at Goldsmiths College in London next month after traveling around the world during her gap year.

Family day out: Fergie was with daughters Beatrice and Eugenie

It's not Ascot: The Princesses join a Mexican wave

Looking the image of her mother Bea chose a jewel green sundress, accessorised with a chain belt, white cardigan and an oversized brown leather clutch.

She and her sister wore of-the-moment black leather gladiator sandals, which Eugenie teamed with a blue sundress and turquoise cuff.

The young Royals were joined by a large group of friends to watch the polo.

The Royals were joined by their friends, including Bea's boyfriend Dave Clark, second from right

Dave, Eugenie and Bea urge on their team

Amongst the youngsters was Bea's boyfriend Dave Clark, who is said to have been given the seal of approval by her parents.

He certainly seemed to be getting along famously with the Duchess, laughing as she pulled a face at the match.

But it was Bea who really held his attention. She was introduced to the 26-year-old by her cousin Prince William, who attended St Andrews University with Mr Clarke.

What a liberty! Dave Clark laughs with Sarah Ferguson

So who do you think is going to win? Bea chats with her boyfriend Dave Clark