Income tax – Investigation. The Administrative Court held that the statutory scheme was such that the defendant Revenue and Customs Commissioners' functions included, not only opening an enquiry into a return under s 9A of the Taxes Management Act 1970 during the enquiry window, but also checking returns without opening a s 9A enquiry, including after the enquiry window had closed, with a view to ascertaining if there was ground to issue a discovery assessment, and that such checking could include, not just re-reading the file, but carrying out investigations and enquiries to see if any further information could be obtained that could shed light on the question.