What a £20m-plus London home has to deliver, where these houses and apartments are, and how a buyer’s adviser secures them before they are marketed.
By Aldo Attanasio d’Aponte – September 10, 2026
What buyers expect from a £20m+ London home
Above £20m, London property stops being a market and becomes a short list. There are perhaps a hundred homes at this level for sale at any one time, most of them never advertised, and the buyers competing for them are not looking for a bargain so much as an absence of compromise. This guide sets out what a super-prime home has to deliver, where it is likely to be, and how the purchase is actually done.
What makes a London home worth more than £20m?
Price at this level is not a function of square footage alone. A house in the wrong street with 12,000 sq ft will struggle to reach £20m; a 6,000 sq ft house on the right garden square in Notting Hill or the right terrace in Belgravia will exceed it comfortably. The buyer is paying for a combination of things that rarely occur together.
The first is the address itself. Super-prime homes sit on a small number of streets and squares whose reputation was settled a century or more ago and has not moved since. The second is privacy. A house that is overlooked, or an apartment with a shared entrance that admits anyone, will be marked down by every serious buyer, and rightly so. The third is proportion: ceiling height, lateral space, natural light from more than one side, a staircase that does not feel like an afterthought. The fourth is condition. At £20m the buyer will almost always bring in their own interior designer, but they expect the building itself to be finished, dry, wired and warm. Nobody at this level wants to spend two years with a contractor.
I would add a fifth, which is less discussed: the quality of the neighbours and of the building’s management. In an apartment building, a badly run freehold or a fractious residents’ company will cost more in aggravation than any service charge. In a house, a neighbouring basement excavation can take three years of a client’s life. We check both before a client offers.
Where are London’s £20m homes?
Almost all of them are north of the river and within a mile or two of Hyde Park. Mayfair supplies the townhouses, generally Georgian, generally on the Grosvenor Estate or close to it, and a townhouse of the right size in the right street trades from £30m upwards. Belgravia supplies the white stucco terraces around Eaton Square and Chester Square and the larger houses off Belgrave Square. Knightsbridge supplies the lateral apartments, including the handful of buildings where a single floor can change hands for £50m or more. Kensington and Holland Park supply the detached and semi-detached villas with gardens, which is what a family buyer with young children and staff generally wants. Notting Hill supplies the garden-square houses, where access to a private communal garden is itself worth several million.
Beyond this core there are two further pockets. The terraces around Regent’s Park have some of the finest houses in the city, and the largest of them have set records that will not be repeated for a generation. North of that, Hampstead, Highgate and the streets around the Heath supply the very large detached houses, with grounds and parking, that simply do not exist further south. The rest of London contributes the occasional exceptional house on the river or in a park, but these are individual events rather than a market.
What do ultra-high-net-worth buyers want beyond the address?
The brief we receive at this level is remarkably consistent. Staff accommodation, ideally with its own entrance. Off-street parking for at least two cars, which in central London is scarcer than a swimming pool. A lift, in any house of more than three floors. Outdoor space that is usable, not just visible: a terrace that seats twelve, or a garden that a gardener can keep in order without a team of five.
Then the entertaining spaces. A drawing room of real scale, a dining room that can be closed off, a kitchen the family will actually use and often a second one for catering. Below ground, the leisure floor: pool, gym, screening room, wine store. Planning authorities in Westminster and Kensington and Chelsea have tightened the rules on basement excavation considerably, so an existing, consented, well-built basement adds real value and a house without one has a ceiling on what can be done.
Two more items have moved from optional to expected. Air conditioning, because London summers are no longer what they were. And genuine energy performance, not because these buyers worry about the bill but because a house that has been properly insulated and re-serviced tends to be a house where everything else has been done properly too.
Why does so much of this market trade off-market?
Because the owner of a £30m house does not want strangers walking through it, and does not need to advertise to find a buyer. The agents who handle these homes keep a short list of people they know can perform, and the house is shown quietly to two or three of them. If none of them proceeds it may eventually appear on a portal, but by then the best buyers have already seen it and passed.
This is the practical reason a buyer at this level uses an adviser. Across twenty years, 78% of the purchases we have secured for clients were off-market, and the proportion rises with price. Our job is to be on the list when the call is made, to have the client’s proof of funds, lawyers and structure ready so that we can move inside a week, and to know enough about the street to say whether the asking figure is realistic. On average our clients have paid 12% below the initial asking price, and at £20m that is a meaningful number.
Discretion cuts both ways. Many of our clients are people whose names would move the price if they were known to be looking. We never disclose who we act for, and we frequently view alone before a client sees anything.
Is demand at the top of the market holding up?
Yes, and it has been more resilient than the tiers below it. Buyers at £20m are not borrowing, so interest rates are of secondary interest; they are choosing between London, New York, Paris and a few other cities, and London’s combination of law, schools, language and time zone keeps it on the list. Meanwhile supply is fixed. Nobody is building new Georgian terraces, and the planning system now actively resists the very large lateral apartment. What exists is what there will be.
That does not mean every asking price is justified. I have advised clients to walk away from houses at this level more often than I have advised them to stretch, and telling a client to wait sometimes costs us a fee. It is usually the right advice. The homes worth £20m are worth it; the ones priced at £20m in the hope of finding a buyer are not.
How Arbitrage can help
We act only for buyers, never for sellers, so our advice on price and on whether to proceed is not compromised. We have advised on £1.5bn of acquisitions since 2006 and have secured most of them before they were marketed. We coordinate with your private bank, tax advisers and solicitors so that the purchase fits the rest of your affairs, and we are used to working with clients who require complete discretion.
Frequently asked questions
How many £20m-plus homes are for sale in London at any one time?
Openly, perhaps a hundred, and the number moves with the season. Far more change hands privately without ever being listed. A buyer relying on the portals alone is seeing a fraction of what is actually available.
Should a buyer at this level use a buying agent?
At £20m the cost of a wrong decision, or of overpaying by a few percent, comfortably exceeds any fee. A buyer’s adviser gives access to homes that are not advertised, an independent view on price, and someone whose only interest is on your side of the table.
Are super-prime apartments or houses the better buy?
It depends on how the home will be used. An apartment in a serviced building suits a buyer who is in London part of the year and wants to lock the door and leave. A house suits a family that lives here, keeps staff and wants a garden. Both hold value if the address is right; neither does if it is not.
What should a buyer check before offering on a £20m house?
Title and lease terms, planning history and any consented works, the condition of the structure and services, neighbouring development plans, and the management of the building if it is an apartment. At this level we also look closely at who the neighbours are and whether the street has any long-running disputes.