Yes but you could keep things from him, he can only work out your taxes and vat etc from information you give him, unless you employ an accountant who audits your accounts the responsibility is on your shoulders not his. A lot of accountants have deals regarding this insurance, the OPs accountant is ripping him off IMO, A fee of around 70 quid which covers all legal and accountants costs during Investigations, is acceptable for a business IMO, and remember HMRC can investigate you and cause all sorts of problems even though your legit, and you cannot claim any money back from them, your accountant will need to be paid if he helps you with dealing with the HMRC. Of course you could always have your accounts audited, it will cost around 4k a week to employ an accountant full time for that pleasure though.