Speculation over the designer of Kate Middleton’s wedding dress was mounting yesterday with a little-known British label reported to be behind the top-secret gown.

Sophie Cranston, of Libelula, is said to have been chosen by Ms Middleton for the all-important creation, according to The Huffington Post in the US.

It follows recent claims that Sarah Burton, of Alexander McQueen, is the designer, with Daniella Issa Helayel, Bruce Oldfield, Jasper Conran and Alice Temperley also reported to be in the running.

Ms Middleton wore a tailored black velvet Libelula coat to a friend’s wedding in January.

Ms Cranston, who won the prestigious Designer of the Year Award at Graduate Fashion Week in 1999, started on Saville Row and at Bellville Sassoon.

She worked for McQueen before setting set up Temperley in 2000 with Alice Temperley.

She started Libelula – which means “dragonfly” in Spanish – after moving to Andalucia in southern Spain to learn flamenco and Spanish.

Ms Cranston returned to the UK and set up her headquarters and now has a studio in Greenwich, southeast London.

According to its website, the label prides itself on creating “beautifully cut, timeless and flattering shapes”.

It also offers bespoke wedding dresses, creating “vintage- inspired couture gowns”.

There has been no comment yet from Libelula itself and St James’s Palace has steadfastly refused to be drawn on any matters concerning the wedding dress.

The bride-to-be is said to be determined to keep the details a secret.