Public liability is not required by UK law for most businesses, which is a true answer that helps almost nobody. The useful question is different: does anybody you work for, rent from or belong to require it, and would a claim against you be survivable if they did not.
The legal answer, and why it is not the operative one
There is no general statutory duty to hold public liability cover in the UK. Employers' liability is compulsory once you employ anybody, and motor insurance is compulsory for road use, but public liability sits outside both. A handful of activities carry their own licensing requirements that reference insurance, and otherwise nobody will prosecute a business for going without. What happens instead is that the work dries up, because the people who hand out work all ask for it.
Who asks for it in practice
Client contracts and purchase orders name a limit. Main contractors check a certificate at induction. Commercial landlords require it in the lease. Markets, village halls, festivals and local authorities will not let a stall or a stand trade without it. Trade bodies and competent person schemes require it for membership. Online platforms and agencies increasingly ask before allocating work. None of these is the law, and all of them are enforced more reliably than most laws.
The test when nobody is asking
Where nothing external requires it, the question is exposure. Does your work happen in places you do not own, near people who are not employees, near property you could damage. A software developer working from home has a genuinely small public liability exposure. A tradesperson in a client's house, a mobile therapist, a market trader, a dog walker or anybody using equipment in a public place has a real one, and the defence costs of a claim usually exceed the annual premium by a wide margin.
What it does not cover, in case that is the actual question
People buy public liability and assume it is a business policy. It answers for injury to third parties and damage to their property. It does not cover your own tools, your own stock, your own vehicle, your income if you stop working, a claim that your advice was wrong, or an employee's injury. Each of those is a different section or a different policy, and a business that bought public liability alone has usually covered the risk it was asked about rather than the risk it has.
Questions people ask about do i need public liability insurance
Is public liability insurance a legal requirement in the UK?
Not generally. Employers' liability is compulsory once you employ anybody, and public liability is required by contracts, landlords, trade bodies and venues instead.
Do I need it if I work from home alone?
Only if people visit or your work reaches other people's property. A home based business with no visitors and no site work has a small exposure, though clients may still require it.
What limit do clients usually ask for?
Whatever the contract names. Where nothing names a figure, size it to the worst realistic claim including legal defence costs rather than to turnover.