A concealed staircase and retracting floorboards complete the theatrical entry
In the quiet streets of Hampstead, where old money and new ambition have long negotiated their coexistence, a Russian tech entrepreneur has placed his unfinished vision on the market — a neo-Georgian shell transformed into a contemporary fortress, complete with a secret Batman-themed basement that no catalogue could have anticipated. Sergey Frolovichev, who helped reshape how a generation finds love through Bumble and Badoo, now offers the proceeds of that $3 billion exit as architecture: 14,500 square feet of engineered comfort, theatrical concealment, and deliberate incompleteness, asking £29.95 million for the bones of something that could become, with another £5–7 million and a willing imagination, one of London's finest private residences. It is a peculiar kind of inheritance — not of family, but of fortune — and the question it poses to its next owner is less about price than about vision.
- A hidden staircase, retracting floorboards, and Dark Knight-inspired lighting announce that this is not a conventional luxury listing — it is a statement of personality pressed into concrete and steel.
- At £29.95 million for an unfinished interior, prospective buyers face an unusual gamble: pay now for potential, then spend another £5–7 million over 18 months before the house becomes truly habitable.
- The tension between heritage and ambition runs through the entire structure — a 1934 neo-Georgian shell by architect C.H.B. Quennell now houses ground-source heating, integrated smart cabling, and a triple-height cantilevered staircase soaring 12.5 metres.
- Frolovichev's exit from the Bumble and Badoo holding company in a $3 billion Blackstone deal funded this project, linking the intimate economy of digital dating to the rarefied world of Hampstead ultra-luxury.
- Draper London projects a completed value of up to £40 million, framing the gap between asking price and finished worth as opportunity — but only for a buyer with both capital and conviction.
A seven-bedroom mansion on Greenaway Gardens in Hampstead has entered the London market at £29.95 million, carrying with it one of the more unexpected features in recent luxury property history: a concealed basement workshop styled after Christopher Nolan's The Dark Knight. The space is accessed through a hidden entrance in the games room, via a concealed staircase and retracting floorboards, and is lined with display cabinets and cinematic ceiling lighting. It is the kind of bespoke architectural indulgence that resists easy replication.
The property is the work of Sergey Frolovichev, a Russian tech entrepreneur who co-founded the dating platforms Bumble and Badoo alongside Andrey Andreev. The 2019 sale of their holding company to Blackstone — valued at $3 billion — provided the capital for ventures of this scale. The original 1934 structure, designed by architect Charles Henry Bourne Quennell in neo-Georgian style, was enlarged and remodelled by architectural practice SHH rather than demolished, producing a hybrid of heritage exterior and thoroughly contemporary interior systems.
The listing is offered on a shell-and-core basis: the structural and mechanical infrastructure — ground source heating, underfloor heating, fresh air ventilation, integrated smart cabling — is complete, but interior finishes remain undone. Buyers should expect to invest a further £5–7 million over 12 to 18 months. Listing agent Draper London projects a completed value of up to £40 million.
The lower ground floor houses a health spa with pool, gym, steam room, and sauna, alongside the media and games rooms. The principal bedroom suite spans the entire first floor and opens onto two roof terraces. Outside, nearly 8,000 square feet of terracing surrounds the property, with a south-west facing garden and plans for a sunken fire pit. A triple-height entrance hall with a cantilevered staircase beneath a rooflight 12.5 metres above sets the tone from the moment of arrival — a residence that asks its next owner not merely to buy it, but to complete it.
A seven-bedroom Hampstead mansion with a concealed basement workshop styled after Christopher Nolan's Batman film has entered the London property market at £29.95 million. The house, situated on Greenaway Gardens, spans roughly 14,500 square feet and represents the vision of tech entrepreneur Sergey Frolovichev, who built his wealth through the dating app platforms Bumble and Badoo alongside co-founder Andrey Andreev.
The basement—the property's most distinctive feature—functions as a design studio accessed through a hidden entrance from the games room. The space draws its aesthetic directly from The Dark Knight, with display cabinets lining the corridor and ceiling lighting that echoes the film's visual language. A concealed staircase and retracting floorboards complete the theatrical entry sequence. For buyers drawn to the property's bones, this basement represents the kind of bespoke architectural indulgence that money alone cannot easily replicate.
The original structure dates to 1934, designed by architect Charles Henry Bourne Quennell in neo-Georgian style. Rather than demolish and rebuild, the architectural practice SHH secured planning permission to enlarge and remodel the existing building, working closely with Frolovichev on the design vision. The result is a hybrid: a heritage shell containing thoroughly contemporary systems and spaces.
The property is being marketed on a shell-and-core basis, meaning the structural and mechanical infrastructure are complete but the interior finishes remain unfinished. Prospective buyers should anticipate spending an additional £5 million to £7 million over 12 to 18 months to bring the interiors to completion. Draper London, the listing agent, projects that once finished, the mansion could command up to £40 million—a substantial premium over the current asking price.
The systems already installed suggest a residence engineered for maximum comfort and control. Ground source heating and underfloor heating run throughout. Fresh air ventilation reaches every room. Integrated cabling for home entertainment and security systems is already threaded through the walls. A triple-height entrance hall features a cantilevered staircase beneath a rooflight positioned 12.5 metres above.
The lower ground floor contains a health spa with swimming pool, gym, steam room and sauna, alongside the media room and games room. The principal bedroom suite occupies the entire first floor width and includes two roof terraces, two dressing rooms and two bathrooms. Six additional bedroom suites are distributed across the upper floors. Outside, nearly 8,000 square feet of terracing surrounds the property, with a south-west facing garden and plans for a sunken fire pit with built-in seating.
Frolovichev's wealth derives from the 2019 sale of the holding company controlling Bumble and Badoo to Blackstone, a transaction that valued the business at $3 billion. That exit provided the capital to pursue property ventures of this scale and ambition. Craig Draper, founder of Draper London, frames the listing as offering "a once-in-a-generation opportunity to create one of the finest new residences in Hampstead"—a characterization that speaks to both the property's potential and the rarefied market in which it competes.
Citas Notables
This sale offers a once-in-a-generation opportunity to create one of the finest new residences in Hampstead— Craig Draper, founder of Draper London
La Conversación del Hearth Otra perspectiva de la historia
Why would someone design a basement after a Batman film? That seems like an unusual choice for a £30 million property.
It's not about the film itself—it's about the aesthetic language. The Dark Knight established a visual vocabulary: clean lines, dramatic lighting, functional luxury. Frolovichev was essentially commissioning a design studio that felt like stepping into a controlled, sophisticated space. The hidden entrance and retracting floorboards aren't gimmicks; they're part of a coherent design philosophy.
But doesn't that date the property? Won't it feel dated in five years?
That's a fair question. The design references are subtle enough—display cabinets, ceiling lighting—that they read as contemporary rather than novelty. And at this price point, buyers are often purchasing the craftsmanship and the vision, not trend-chasing. The real value is in the infrastructure and the scale.
Why is it being sold unfinished? That seems risky for a seller.
It's actually strategic. The shell-and-core approach lets the buyer complete the interiors to their own taste. Frolovichev has already absorbed the cost of the structure, the systems, the planning permission. A buyer gets a fully engineered building and the freedom to finish it their way. It also means the price reflects the work done, not speculative interior costs.
What kind of buyer are we talking about here?
Someone with serious capital—not just the £30 million purchase price, but another £5 to £7 million for completion. Someone who values privacy, technology, and bespoke design. The Batman basement suggests Frolovichev himself was that buyer. Now he's passing that vision to someone else.