SEX! SEX! SEX!

Ed Kienholz was a pioneer of assemblage, or "funk" art, in the 1950s and 60s, a movement dedicated to collecting society's debris from flea markets and junk shops to make artworks that provoked our social conscience. He expanded the form to installation scale and many works – State Hospital, for example, which showed two abandoned inmates on a bed in a psychiatric unit and was inspired by his time as a hospital attendant – were based on his own experiences.

Nancy and Ed's biggest environmental sculpture, The Hoerengracht (Whores' Canal) – a garish, life-size depiction made over five years in their Berlin studio of a 1980s Amsterdam brothel district – will stand alongside paintings from the gallery's permanent collection of Dutch masters depicting prostitution scenes from the 17th century. It will be the first time that the gallery has exhibited a modern installation. "It's as good as it gets," says Nancy. As a point of interest one of our dear WOF colleagues lived in the same street no. 133 Herengraght and regularly saw and spoke to the selfsame ladies, though strictly in a neighbourly fashion.

When the letter from Nicholas Penny, the director of the National Gallery, arrived earlier this year inviting her to exhibit The Hoerengracht – whose name is a pun on the elegant street Herengracht or "Gentleman's Canal" – because he wanted to compare it to the Dutch old masters such as Vermeer and De Hooch, Nancy thought it must be a joke.

Nancy and Ed started making the installation in 1983. They paid the sex workers 50 guilders a head to be allowed to enter and photograph their rooms to gather information. She is tickled that their work is now being seen as a historical document of the red light district of the 1970s and 80s.

The Hoerengracht is going to be shown alongside paintings by Steen, Van Hoogstraten, De Hooch and Vermeer, pictures which at first glance appear to show gentle Dutch townscapes or serene Delft interiors, but on closer inspection depict tableaux of prostitution and sensual pleasure.

"Unlike the old masters, The Hoerengracht has nothing to do with good taste. It's a sleazy piece of art with dirty surfaces and tacky artefacts."

Kienholz: The Hoerengracht opens at the National Gallery, London WC1 on 18 November