3.3.4. Bank statements must be on official bank stationery, or be electronic bank statements from an on-line account (defined as one that operates solely over the internet and sends bank statements to its customers electronically) which are either accompanied by a letter from the bank on its headed stationery confirming that the documents are authentic or which bear the official stamp of the issuing bank on every page.
3.3.5. The bank statements must cover the specified periods as described in the Immigration Rules for each of the sources of income relied upon.
3.3.6. As an alternative to a bank statement we will also accept:
a building society statement or pass book; or
a letter from the bank or building society; or
a letter from a financial institution regulated by the Financial Services Authority or, for overseas accounts, the appropriate regulatory body for the country in which the
institution operates and the funds are located. The financial institution must not appear on the list of excluded institutions under Appendix P of the Immigration Rules.