EM1540 - Opening the Enquiry: Which Year
TMA70/S29
FA98/SCH18/PARA 41
Where you have information that suggests possible omissions are likely to have continued into a later year, enquiries should usually be opened by a Section 9A or Para 24 notice into the most recent return.
If the normal time limit for making an assessment to recover tax for which there is a potential discovery assessment position is about to go out of date, you may want to consider the use of formal information powers to obtain the information needed to decide what, if any, assessment must be made, see CH23520.