The earliest example is a sharp little A-line hessian number, with buckle neck, designed by Mary Quant and dating from 1964. However, it could be confused with a dress from 1994, such are the striking similarities between many of the originals and what is currently for sale, proving perhaps that, after years of relentless reinvention, there is little left that is truly new.
It has taken 15 years of searching sale-rooms, donations and luck to bring together this choice collection of short, sharp minis. A gem, like the pale pink Mary Quant jersey dress, was unearthed by chance in 1989 at the back of a boutique. A tiny cream wrap-over mini-skirt was a gift from Sixties style icon Jean Shrimpton.
Among the more novel numbers are the teeny candy-coloured paper dresses made by the Mars Corporation in the United States in 1967 and donated by an American architect. 'Paper was certainly an experiment at the time,' says Valerie Mendes, Curator of Textiles and Dress and organiser of the display. 'It was all part and parcel of the Sixties mentality, the throwaway society.'
Much might have been thrown away but little has been forgotten. The Sixties was her era. 'I just loved it, the clothes were so optimistic. I suppose seeing a girl's legs then was extraordinarily erotic. In a way it was an unconscious exploitation of young women, especially when they were photographed all twine-toed with big staring eyes. We all looked like children.'
These days they seem far from erotic or shocking; terry towelling and thick jersey are not so sensuous anymore, and short hemlines hardly raise an eyebrow. But to anyone over 40, such vintage names as Courreges, Cardin, Biba, Mr Freedom, Ossie Clark and Celia Birtwell will doubtless bring tears to the eyes. As will the original prices - pounds 3 for a floral bell-sleeved shirt dress.
With a nod to 1994, three dresses by the contemporary fashion designers Liza Bruce, Max Mara and Thin Line will also be displayed.
Thoroughly Modern Minis opens at the museum next Tuesday, along with the re-opened main dress collection.