Enter this extraordinary time machine of a house with your imagination primed to take part in the plot. The Georgian terraced house belonged to the eponymous performer-designer-scholar from Escondido, California, who dedicated his life not only to restoring his house but also to raising the ghosts of a fictitious Jervis family who might have inhabited it over the course of two centuries. Dennis Severs created a replica of Georgian life, without electricity but with a butler in full 18th-century livery to light the candles and lay the fires -- for the Jervises. The rooms are shadowy set pieces of rose-laden Victorian wallpapers, Jacobean paneling, Georgian wing chairs, baroque carved ornaments, "Protestant" colors (upstairs), and "Catholic" shades (downstairs). The "Silent Night" candlelit evenings, each Monday, are the most theatrical and memorable way to "feel" the house. Private visits by special arrangement are possible. COST: £8 for Sun., £5 for Mon. open house; £12 for candlelit Mon. evenings. Tube: Liverpool St.