Fenchurch Advisory Partners LLP v AA Ltd

Even where engagement terms and fees are extensively negotiated and substantial professional work is performed, no binding retainer arises absent the contemplated signed engagement letter; but the recipient of the freely-accepted services is unjustly enriched and must pay a restitutionary quantum meruit reflecting the reasonable value of the work done, excluding any success/transaction fee that would only have accrued under the unconcluded contract.