This building was erected on the site of some old offices connected with the Treasury; it was commenced in , the architect being John Soane, esq.; it is an highly enriched building of stone, the order the Corinthian of the Temple of Jupiter Stator at Rome. The principal elevation consists of stories, besides a basement fronted by a sunken area, guarded by a handsome ballustrade of stone; the succeeding stories are ornamented by attached columns resting on a stylobate, and crowned with the splendid entablature of the original: at each end the columns are insulated, and form a pavilion, which is returned to the side of the building in Downing-treet, the pavilion being composed of columns; the or attic story is partially concealed by the ballustrade which surmounts the entablature.

In the general style of finishing and fitting up the interior, simplicity united with elegance has been adopted. The council chamber is peculiarly rich and imposing in effect; it is adorned with a coved ceiling divided into compartments, each enriched with ornaments, at sides of which are lantern lights, extending the whole length of the room; each side of the apartment is distinguished by Scagliola columns supporting an ornamental entablature, of which form window frames, and doorways. At the ends are fireplaces, and at the side towards the stairs are doorways.

The building is not yet finished, and if the present line of front is adhered to it seems as if it would encroach most inconveniently on the street; it will probably remain in an unfinished state till some expedient can be devised to remedy the present awkward arrangement. The architect proposed to ornament that dull avenue, , with triumphal arches, which from its confined situation, and the want of a vista, would, however grand and expensive the subjects might be, have been perfectly outre and useless as ornaments. If completed, the building will extend feet, of which about feet is finished.