The Office of Tax Simplification is going to look at the merits and barriers associated with the current 5th April end of UK tax year.  My personal view is that a move which aligns with the end of the calendar year will simplify many aspects of personal taxation, in particular for those many clients with tax filing obligations overseas, where many countries apply the calendar year end.  Also those with investments overseas will often receive investment reports to the calendar year end, and therefore require adjustment for the completion of UK Tax Returns. Those adjustments can sometimes lead to errors, and so a more simplified system will potentially lead to fewer tax errors.