37 And 38, Charles Street W1

A grand town mansion created in 1890 by the rebuild-conversion of two mid-18th-century houses. The architect was W. Allwright of Turner Lord, commissioned by A C Baring, later Lord Revelstoke, to create a setting worthy of his collection of French antique furniture and objets d'art. The building was designed in French Rococo style. Internal embellishments were added in 1900 and 1901 by Lord Dartmouth, and minor alterations were made in 1927 by Clough Williams Ellis to convert the building into the English Speaking Union.

The exterior is refaced in Portland stone ashlar with a slate roof; part of the original brickwork survives to the rear. The building comprises four storeys with a basement and dormered mansard. The facade presents a symmetrical composition of three major bays. The central entrance bay features vermiculated rustication to the ground floor, with a polished granite columned Doric porch, the columns reputedly sent from St Petersburg. Giant pilasters rise through the first and second floors, flanking elaborately framed central windows contained in a semicircular arched channelled niche; a festooned oculus appears in the tympanum of the third floor. The flanking bays each contain three windows: semicircular arches in channelled ground floor openings; flat arches on the first floor below an exaggeratedly broad pediment with enriched tympanum, surmounted at second floor level by an ornate oeil-de-boeuf and flanked by windows with eared architraves and mask keystones. The third floor windows have eared architraves, each with a pair of consoles supporting the crowning cornice. A continuous balustraded parapet with urns runs across the top. Moulded string and sill courses feature throughout, and rich Rococo wrought iron area railings with lampholders enclose the frontage.

The rear elevation retains some 18th-century stock brickwork to the left, while the right side features an 1890s staircase bay with chamfered corners. Lower floors are faced with ashlar, including a female mask keystone flanked by griffins and an iron balustrade. A stone wall with a semi-circular arch and two lamp brackets connects the main building to the 1890 former mews building, now offices. This mews structure is faced with ashlar (with some brickwork to the rear), has a mansard slate roof, and comprises one storey with attics. It features a central curved bay with a male mask and swags flanked by two pilasters on each side, with two further bays containing panels with shell moulding and swags beneath ground floor windows. The left window has a dormer carved with martial achievements.

The interior is spectacular. The Small Drawing Room retains circa-1740 dado panelling. Eight rooms are panelled in very high-quality mid-18th-century French panelling, believed to have come from Parisian hôtels. The Drawing Room contains 18th-century French painted doors. Fine fireplaces throughout include a Robert Adam fireplace in the Drawing Room, originally at Derby House, Grosvenor Square; an Italian inlaid marble fireplace to the ground floor; a marble fireplace in the Small Drawing Room with gold urn, paterae and ram's heads; and a similar marble fireplace in the Wedgewood Room with large gilded brackets.

An elaborate full-height staircase hall was constructed in 1890, lined with Belgian marble and featuring an elaborate Imperial staircase with cast iron balustrading incorporating the Baring shield. The ceiling painting is by Pierre Victor Galland (1822-1892), who was also responsible for the painted panels in the Wedgewood Room. The Wedgewood Room has elaborate plastered panelling of circa-1890. Many elaborate plastered ceilings feature throughout, including a 1900 ceiling to the Drawing Room and a 1901 ceiling to the Small Drawing Room, both added by Lord Dartmouth after a financial crisis in 1893 had caused work on the property to stop. The interior represents a spectacular example of grand European decoration and is an early example of this type of decoration in Mayfair.