Pilgrimages are being made to an unusual fashion shrine. For the past three months, visitors have coursed through the gates at Kensington Palace to pay their respects to the designer princess.

They file impatiently through the state rooms and pause in front of the royal ceremonial dress collection, billed as being a “unique display which conjures up the excitement and drama of entering society. Hear the rustle of silk and hushed whispers as the doors open and you are on the brink of being presented at the Royal Court ...”

The Gucci-accessories brigade displays a flicker of interest in a collection of dresses lent by the Queen that includes gowns by Sir Hardy Amies and Sir Norman Hartnell, but passes swiftly on.

They plunge down a stone staircase into a white basement room and there they find 14 dresses on tailor’s dummies in four floor-to-ceiling glass cabinets - the Diana, Princess of Wales dress collection.

Christopher Gidlow, education manager for the historic royal palaces, says:

“The reaction has been quite incredible. There was a feeling that interest in Diana had died down, that people weren’t interested in her any more, but the response has been phenomenal.”

On one Sunday there were 13,000 visitors, compared with the average 800 expected before the princess’s dresses went on public view, and the number of school groups has doubled.

The royal dress collection is of interest to school groups for its historical value, but Mr Gidlow says it is particularly suitable for technology and textiles students.

“The fabrics are very expensive and GCSE students wouldn’t otherwise have access to them but we have samples of some of the materials which they can come along and handle.”

The value of some of the fabrics is said to be “incalculable” but even the more everyday closely-woven wool cloth which was the basic material for uniform coats would cost pound;60 a square yard.

As accoutrements, what Diana’s 14 dresses do more eloquently than the state rooms and fine costumes is throw lght on what it means to be royal. In the audio commentary designer Catherine Walker says: “In the early Eighties it felt as if Diana needed a sort of royal uniform that was a legacy from 18th century court dressing where etiquette decreed that sartorial finery and rich apparel were appropriate.”

A dress by the designer demonstrates the thought that went into her clothes. The white silk crepe dress embroidered with sequins and bugle beads was worn during a state visit to Brazil. Walker recalls that shortly before the visit Brazil had been beaten by Argentina in the World Cup and the country was virtually in mourning. She was told the gown should not be in green, yellow or blue - the home team colours - lest it remind people of the defeat and certainly not in the victors’ colours of blue and white.

The gowns - on loan from American millionairess Maureen Rorech-Dunkel, who bought them for almost $1 million at Christie’s in New York in 1985 - sometimes appear characterless on the dummies: a cream 1987 Zandra Rhodes creation, with a bizarre hemline and padded shoulders, looks particularly peculiar. But somehow Diana could wear anything. The commentary says designer Bruce Oldfield once told her: “When you are 6ft 3in in high heels you could wear a sack and still be noticed.”

The exhibition, which is expected to raise pound;150,000 for the Historic Royal Palaces and the Diana, Princess of Wales Memorial Fund, is a fitting tribute to the catwalk princess. In her 17 years in public life she was criticised for many things, but not often for her dress sense. Bruce Oldfield says she was “the perfect model and ambassador for us all. She created worldwide interest in British fashion.”

Despite the frocks and the verbal flourishes of the commentary, it all seems a bit flat. But then you see the photograph of Diana swirling around the dance floor with John Travolta after a White House dinner in 1985 and you get a glimpse of the dresses in all their glory.

Kensington Palace, Kensington, London W8. Tel: 020 7937 7079. www.royal.gov.ukpalaceskensingt.htm School parties must book; admission pound;6.10. Open October-March, 10am-4pm.