In legal practice, carrying on business describes factual commercial activity pursued with continuity, usually from a fixed place or through agents, rather than a one‑off transaction or mere investment holding. It is a context‑dependent expression used across company law, civil procedure, partnership, insolvency and tax, with its content drawn from legislation and case law rather than a single, universal definition.Key indicators often include: maintaining a place of business or UK/Irish establishment; employing staff or agents; entering and performing contracts habitually within the jurisdiction; keeping local bank accounts; marketing and holding out to customers locally. Passive shareholding, isolated sales, preparatory steps, or a mere website accessible from the jurisdiction are usually insufficient without more.In partnership law, the core test (Partnership Act 1890) is persons carrying on a business in common with a view of profit. For overseas or unregistered companies, “carrying on business” informs obligations to register a UK/Ireland establishment and the court’s power to wind up entities operating locally. It also affects service of proceedings, jurisdictional gateways, venue, consumer/business regulation and tax exposure.Usage is broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland, though Scottish firms have separate legal personality and Irish company law refers to carrying on business “in the State.”