How much non-business information must a self-employed taxpayer provide to HMRC in response to an information notice, and when is the taxman legitimately allowed to go on ‘fishing expeditions’ to gain info when they think there is a disparity in a tax return? Well, all HMRC need do is show that their request for information is reasonable. Any disparity may have an innocent explanation but it is part of HMRC’s duty to determine if that is the case. And that can include studying personal bank accounts.