Information powers: TMA70/S20: section 20(3) alternatives
Before considering the issue of a Section 20(3) notice to a bank, you should first try to obtain the information from the taxpayer, if necessary by way of the appropriate statutory notice.
Furthermore, if the documents required relate to the account of a spouse, civil partner or domestic partner, the issue of a notice under Section 20(3) to the spouse or partner, should be considered in appropriate cases before an approach is made to the bank EM10122.
If the taxpayer claims not to have the bank statements or other documents, or to have lost or destroyed them and clearly indicates that he will not provide duplicates, you should ask the taxpayer for a mandate to allow you to approach the local branch of the bank direct. You should make the taxpayer aware that the bank may charge him for the information provided. The procedure to be followed where the taxpayer indicates his willingness to give you a mandate is set out at EM10060+.
Where such a mandate is not furnished and you consider that the most practical way to obtain the required documents (or, exceptionally, to check information which the taxpayer has provided) is by way of an approach to the bank under Section 20(3), you must follow the arrangements with British Bankers Association.