LONDON | Mon Apr 18, 2011 - Not since Janet Jackson's "wardrobe malfunction" has an outfit sparked so much debate.

The design and designer of Kate Middleton's wedding dress has been the subject of endless speculation since Prince William and his bride-to-be announced their engagement last year.

A bridal dress designed by Libelula fashion label's founder Sophie Cranston is seen in an undated publicity photo in London. / Reuters

Veteran designer Bruce Oldfield, Alexander McQueen creative director Sarah Burton, Alice Temperley and even Jasper Conran have all been named as possible designers of the gown. And now a relatively unknown designer, Sophie Cranston, is in the frame.

Huffington Post royal correspondent Yvonne York reported that Sophie Cranston of label Libelula has been chosen to design what is already one of the most-talked about dresses of the decade.

Middleton wore a Libelula coat to a friend's wedding earlier this year.

A spokeswoman for the label said it had no comment. The label's web site had gone down by midday on Monday.

If she goes with Cranston, Middleton would be following in the steps of her fiancé's late mother, Princess Diana, who chose relatively unknown designer Elizabeth Emanuel to design her dress for her marriage to Prince Charles in 1981.

Emanuel recalled this year that the intense media interest in the dress required strict security measures.

She said she had to bring in security guards and put Diana's dress in a safe every night to fend off reporters who camped out on the doorstep, gawped through the windows and rummaged through the rubbish bins looking for clues.

"We used to leave bits of different coloured threads and things to put them on the wrong track and we had to put blinds up so that people couldn't peer through the windows," Emanuel said.

Although not a household name, Cranston does have strong credentials. A former Graduate Designer of the Year -- an accolade she shares with the likes of John Galliano -- she worked with McQueen and Temperley before founding Libelula after moving to southern Spain to learn flamenco and Spanish.

Libelula is Spanish for dragonfly.

The royal wedding is on April 29 and will be one of the most-watched events of the year, with some two billion people worldwide expected to tune in to TV coverage.