for the designer that people did not know who it was

The fashion world is desperate to know who Kate Middleton will pick to design her wedding dress when she marries Prince William in April - and the palace's silence is only fuelling the feverish speculation.

"It would be better for the designer that people did not know who it was," said Sasha Wilkins, a fashion blogger known as "LibertyLondonGirl". "Once they announce the name of the designer, that designer's life is going to be hell."

This was the case three decades ago when David and Elizabeth Emanuel were chosen to design the wedding dress of William's mother, Princess Diana, when she married Prince Charles.

"They were stalked, literally," Wilkins says.

This time around, palace officials are giving nothing away, saying that Kate, 29, and her 28-year-old royal fiancee have both agreed to keep some of the details of their big day on April 29 a secret.

But in the absence of any official information, speculation is rife.

A photograph of Kate's sister and mother coming out of the London shop of designer Bruce Oldfield last month was enough to cause the paparazzi to camp outside the boutique day and night in hope of spotting the bride-to-be.

Oldfield was one of Diana's favourite designers and made the wedding dresses of Queen Rania of Jordan and of British socialite Jemima Goldsmith when she married Pakistan cricketer Imran Khan - but he is keeping quiet.

British press speculation meanwhile has covered almost every major British designer, from John Galliano to Stella McCartney and even Victoria Beckham, although Wilkins believes such a big name would overshadow the gown too much.

However, there is little chance that an inexperienced newcomer will be asked to design the year's most talked-about dress, and steady hands such as Philippa Lepley, Jenny Packham, Amanda Wakeley or Jasper Conran - all of them well-known for their bridal gowns - are also likely candidates.

"Whoever designs this dress needs a lot of experience," said Fiona McKenzie Johnston, associate editor of luxury magazine group Conde Nast International.

"They need experience to design a beautiful wedding dress, that's going to stand up all day long, that's going to look amazing when photographed by cameras, on television, that is not going to be dwarfed by Westminster Abbey."

Oldfield - while keeping tight-lipped about any role he may have - predicted that the dress would be reasonably modest, and with a veil.

"I'm sure the dress is going to be modest in terms of coverage, it has to be," he told US television.

"It will have sleeves, it has to have sleeves. You can't walk down Westminster Abbey in a strapless dress. It just wouldn't happen.

"It has to suit the grandeur of that aisle, it's enormous. I can predict she will wear a veil."

The dress must also reflect the times as Britain emerges from a deep recession, and palace officials said after the couple's engagement last year that they were "mindful of the economic situation" in planning the wedding.

Commentators say that Kate is unlikely to pick something similar to the fairytale dress worn by Diana in 1981, made of ivory silk with huge bouffant sleeves and a 25-foot (eight-metre) train.

But it will likely be either white or ivory and most believe it will be made out of natural silk, embroidered by hand - even if the fabric must be imported after the last British silk farm, at Lullingstone, closed in 2004.

One thing that is certain is that imitation dresses will be rolling off the production lines within hours of Kate stepping into Westminster Abbey.

"It will be interesting to see how quickly someone will come up with a version of it. The factories will be making it within seconds," said Peta Hunt, fashion director at You and Your Wedding magazine.

Kate is already on her way to being a style icon - the blue Issa dress she wore when the couple announced their engagement and the cream Reiss dress she wore in Mario Testino's official photograph have flown off the shelves.