If you provide services or give advice as part of your business, you need to ensure your business is protected if legal action is brought against you for injury, property damage or financial loss because you did something (or failed to do something) whilst you provided those professional services. Commonly, professional indemnity insurance is described as covering an act, error, omission, or breach of professional duty.
This form of coverage essentially covers the advice which a professional would give for a fee. Many professions are done on just an advice basis, with no physical work taking place.
Many people confuse public liability cover and professional indemnity insurance. Liability will cover physical damage to property or persons as a result of your negligence. Indemnity, however, is purely for non-tangible advice which is followed causing a loss.