Conflict of interest: acting for vendor and purchaser

You are sole director of a small architectural practice in Manchester. For the past nine years you have acted for Client A, a regional residential developer, on a steady stream of small-site appointments. Client A approaches you on a Monday morning with what they describe as a straightforward instruction: they hold a residential consent on a 0.4 hectare brownfield site in Salford and have decided to sell the site rather than build it out. They want you to prepare a short vendor's pack drawing on the consented scheme, attend a site visit with their commercial agent, and answer technical queries from interested purchasers. The fee proposal is generous and Client A wants the pack ready within ten working days. Two weeks later, an unfamiliar party, Client B, telephones the office. Client B is a small housebuilder you have never worked for. They tell your office manager that they have been shortlisted to bid on a site in Salford and would like your practice to carry out due diligence on the consented scheme, prepare a feasibility appraisal to test whether the consented layout could yield two additional units, and produce a pre-bid risk register. Client B wants this delivered within ten working days to meet the vendor's deadline. When you read Client B's brief in detail you realise the site is the same Salford site you are already preparing the vendor's pack for. You have not yet told Client B that you act for the vendor, and Client B has not yet been told the vendor's identity by the agent. Client A telephones you the next morning, having heard a rumour that Client B has approached you, and asks you to "be helpful" with their questions so the sale completes quickly. The ARB website notes that a sole practitioner was referred to the Professional Conduct Committee last year in a strikingly similar fact pattern, resulting in a reprimand and a published decision. Your practice has no formal conflict register.