The country estate of the English neo-classical architect Sir John Soane will open to the public next spring after a £12m conservation project that painstakingly restores his distinctive vision. Soane built Pitzhanger Manor in the early 1800s in Ealing, the west London suburb that was then a rural village, to host his growing art collection and to entertain friends and clients. Sold after less than a decade amid family difficulties, the architect’s “jewel box” weekend retreat served for much of the 20th century as a local library.