What a buying agent actually does in prime central London, from the brief to the keys, why the best stock never reaches the portals, and how the fee is earned.
By Aldo Attanasio d’Aponte – September 9, 2026
The role of a buying agent in prime central London
A buying agent is the one person in a London property transaction who works for the buyer. Everyone else, the selling agent, the developer’s sales team, the portal, is paid by or serves the other side. In prime central London, where a large share of the best properties are sold quietly and the difference between a good purchase and a poor one can be measured in millions, that distinction is the whole point of the service.
Why is prime central London different?
Prime central London is not one market. It is a set of small, opaque, overlapping markets, each with its own pricing logic. A first-floor flat on a garden square in Kensington and a lateral apartment in a serviced building in Knightsbridge might cost the same per square foot and behave completely differently as assets. Within a single street, one side may sit above a tube line, one building may have a freeholder who has neglected the roof for a decade, one house may have a basement that was never signed off.
The information a buyer needs to make sense of this is not on the portals. It sits with the agents who have sold on that street for twenty years, with the managing agents, with the surveyors and the solicitors who have seen the leases. A buyer arriving from Milan, Geneva or New York for three days of viewings has no way to reach it. A buyer who has lived in London all their life usually does not either, because they buy a house once a decade and the market has moved in between.
Then there is the question of what is for sale at all. In the districts we work in, a large proportion of the best homes change hands before they are advertised, or without ever being advertised. Owners at this level value privacy. Selling agents prefer a quick, discreet sale to a qualified buyer over a public campaign. If you are relying on the portals you are seeing the residue of the market, not the market.
What does a buying agent actually do?
The work runs in five stages and it is worth being precise about each, because the value is in the detail rather than the label.
The brief. We begin by understanding what the property is for. A family home for ten years, a pied-à-terre used forty nights a year, a rental investment, a base for children at university: each of these points to different buildings, different lease lengths and different price sensitivities. Most clients arrive with a district and a budget. Our first job is to turn that into criteria that can be tested against real properties, and sometimes to challenge the district.
The search. This is where a buying agent’s network earns its keep. We speak to selling agents before they launch, to owners we know may be considering a sale, to developers with stock not yet released, to solicitors and private bankers who hear of a change in a family’s circumstances. Across our own acquisitions since 2006, 78% have been secured off-market. That figure is not a boast about cleverness; it is a description of how this part of London works.
The filtering. A buying agent views first and discards most of what they see. The client is shown a short list, each with an honest account of the problems as well as the merits: the lease with 68 years left, the service charge that is about to double because of a cladding programme, the planning history that suggests the neighbour will be building for two years. A client’s time in London is expensive. It should be spent on properties that can actually be bought and that they would actually want.
The negotiation. Asking prices in prime London are opening positions. We build the case from comparable evidence, condition, lease terms, time on the market and the seller’s own position, and negotiate from that evidence. Our average purchase price is 12% below asking. On a £4 million purchase that is a saving that pays the fee many times over, and it comes from knowing what a property is worth, not from being aggressive.
The transaction. From accepted offer to completion, prime London purchases fail for avoidable reasons: a slow solicitor, a survey that raises a question nobody answers, a lender’s valuer who does not understand the building, a seller who receives a higher offer while the buyer’s side dithers. A buying agent manages the timetable, chases the professionals and solves problems as they appear. We also coordinate with the client’s private bank, tax advisers and solicitors, because a purchase at this level is one line on a wider balance sheet and should be structured accordingly.
What is the difference between a good buying agent and a poor one?
Three things, in my experience.
The first is willingness to say no. A buying agent paid on success has an incentive to close. The good ones resist it. I have told clients to wait a year, or to walk away from a house they loved, and it has cost us a fee more than once. It is usually the right advice, and it is why most of our clients come by word of mouth.
The second is independence from the selling side. A buying agent who also sells property, or who is paid introduction fees by developers, has divided loyalties however carefully they are managed. At Arbitrage we act only for buyers and occupiers. We have never taken an instruction from a seller and we do not intend to.
The third is depth in a specific market. Prime central London is a small geography. An agent who claims to cover the whole of the south east cannot know what a particular building on Cadogan Square is really worth. Twenty years in the same streets is what allows us to say, with some confidence, that a price is wrong.
How is a buying agent paid?
Arrangements vary across the industry. Ours is a success fee, calculated as a percentage of the purchase price, payable on exchange of contracts and agreed in writing before we start. There is no retainer. If we do not buy, we are not paid. I prefer this structure because it keeps our interest aligned with the client’s outcome rather than with the length of the search.
How Arbitrage can help
We have acted exclusively for buyers in prime central London since 2006, advising on £1.5bn of acquisitions and buying more than 500 homes for private clients, family offices and international investors. If you are beginning a search, or have been searching for a while without result, a short conversation will tell you whether we can help and how we would approach it.
Frequently asked questions
Do I need a buying agent if I already know London well?
Knowing London and knowing what is for sale this month are different things. Most of our clients know the city; what they lack is access to the properties that are not advertised and the evidence to price them correctly.
How long does a search in prime central London usually take?
Anything from a few weeks to a year. It depends on how specific the brief is and how rarely the right property comes up. A good agent will tell you at the outset whether your brief is one that the market can satisfy quickly.
Can a buying agent help if I am buying from overseas?
Yes, and this is where the role matters most. We view on your behalf, report in detail, arrange video viewings, and coordinate with your bank and solicitors so that the transaction proceeds while you are elsewhere.
Does a buying agent replace my solicitor and surveyor?
No. We recommend and coordinate them, but the legal work and the survey are done by independent professionals acting for you. Our role is to make sure the right questions are asked and the answers are acted on.
Will the seller’s agent be hostile to a buying agent?
Rarely. A represented buyer is a qualified buyer with finance and advisers in place, which is what a selling agent wants. Many of our best off-market introductions come from selling agents who know we will not waste their time.