Mansion House, Cowley Street, Westminster

Property Summary

Mansion House is one of Westminster’s grandest private residences — a magnificent Georgian property of over 11,000 sq ft, originally designed by Horace Field and meticulously restored to combine royal-era grandeur with world-class modern amenities. Behind its stately façade, the home features seven ensuite bedrooms, a sweeping oak-panelled staircase, and interiors of extraordinary craftsmanship. With views over Big Ben, the Houses of Parliament, and Westminster Abbey, the property also offers exceptional leisure facilities including a private pool, gym, spa, cinema, and bar. Rarely does a residence of such historical significance and scale come to market in central London.

Key Features

• Bedrooms: 7 (all en-suite; principal suite with dual bathrooms, dressing room, and terrace)

• Bathrooms: 7 + guest facilities

• Reception Rooms: Grand oak-panelled drawing room, formal and informal lounges, bar, and games room

• Leisure & Wellness: 10-metre swimming pool, spa with sauna, steam room, jacuzzi, gym, and private patio garden

• Entertainment: Home cinema, bar, and walk-in wine room

• Architecture: Georgian design by Horace Field featuring high ceilings, ornate cupola, grand staircase, and marble detailing

• Technology: Integrated AV and lighting systems, comfort cooling, 8-person lift

• Outdoor Spaces: Roof terrace with views over Westminster Abbey and the Houses of Parliament, landscaped patio garden

• Location: Cowley Street, Westminster — within walking distance of St James’s Park, Whitehall, and Parliament Square

Design Comment

Fully restored to the highest specification, Mansion House is move-in ready yet offers scope for personalisation through bespoke interior design, art curation, or luxury furnishing. The expansive leisure level could be further customised with wellness technology, while the roof terrace invites enhancement with outdoor dining or garden design worthy of its panoramic Westminster views.

Development Consultations

To assist potential buyers of this property to understand their full design and development options, Janine Stone & Co. is able to provide complimentary design concept and development consultations. It can be arranged for these consultations to take place at the property or in our London studio. Janine Stone & Co. will provide guidance on architecture, refurbishment and planning considerations, in addition to helping interested parties to develop their early design ideas, into floor plans with estimated project costs and timelines for realisation.

Should a successful acquisition take place, we would be happy to take these initial concepts, through to a full concept and subsequent planning, design and build phases.