A holiday cottage on top of London’s Queen Elizabeth Hall? In the form of a boat? Yes indeed: it’s to some extent an art installation, curated and programmed by Artangel, but it is also an entirely habitable little home, courtesy of Alain de Botton’s ‘Living Architecture’ company.

This resulted from a competition which drew some 500 entries, won by architect David Kohn with artist Fiona Banner. Their entry came with a narrative: it was inspired by Conrad’s 1903 novella ‘Heart of Darkness’ narrated in a boat on the Thames by a former Congo steamboat captain. To that they have added some of the epic obsessiveness of Sir John Soane.

Conrad himself had captained just such a river steamer in the 1890s, called “Le Roi des Belges”, since King Leopold II personally owned the Congo Free State at the time. And “Le Roi des Belges” is the name Kohn and Banner have given this rooftop boat/house.

You get to it (if you’ve paid to stay there) via a temporary lift rising from the QEH service yard. At the top, you find a scaffolded gangway leading across the roof of the auditorium to the stern of the ‘boat’. It’s steel-framed, with a riveted aluminium hull and stained plywood superstructure. Inside, toilet and shower room are behind burgundy leather curtains to either side of a stern anteroom as you enter. Then comes a compact kitchen/diner with a Soanish octagonal antique table and a multiple-opening panel for maps and pictures on the wall.

Finally you’re into the bedroom/living room at the prow. The place is intended for two people: the double bed can divide and roll sideways into two beds either side of the cabin. A semicircular banquette with bookshelf beneath occupies the front. The style is eclectic: not nautical, not hotel-like, not minimalist. 

It’s been a little simplified from the competition entry - not much happens in the ‘bridge’ upstairs, for instance, which was going to have more habitable space, though you can get into it via a loft ladder, and from there out onto an open deck. Three wind turbines on top of the mast provide up to 75% of its power needs. Power cables and plumbing run from it beneath the walkway to the QEH services.

It’s all about the views: Waterloo Bridge, the National Theatre, Somerset House, the London Eye, as you’ve never seen them before. Guests are expected to indulge in contemplation about the city and record their feelings in a big log book. 

It’s bonkers but curiously appealing. The first six months’ rentals sold out in a few minutes. The second six month period goes on sale on January 19. At the end of 2012 it will be looking for a new home. Any offers?