UK Self-assessment tax returns - late filing

Three million people have not yet filed their self-assessment tax returns in the UK. Last year one million were late - that's £100 million into the Chancellor's coffers in penalties not to mention interest charges !! Money for old rope ? 

Individual taxpayers have 9 months to file a self-assessment tax return after the tax year end on 5 April each year, and yet one million fail to do so. Why ? 

Within each year I file tax returns for clients and approximately 40% of those are filed in the final two months  before the 31 January deadline. This, despite sending reminders each year. 

I have thought about this many times, why ? Apathy, fear, finances, cash-flow ?

Is there a misconception that once a tax return if file and tax due has to be paid there and then ? A self-assessment tax return can be filed and time after 5 April each year and HMRC will send a bill if tax is due and payable but that does not have to be paid until 31 January of the following year.

Are people afraid of what they might have to pay and stick their heads in the sand for as long as possible ? Isn't it better to know the situation and to plan for any outcome ? Getting the tax return done quickly gives breathing space (up to 9 month) to find a solution and to look at possibilities to legitimately reduce the final tax bill.

Is too much time given to file the tax return ? Does this create apathy ? In other countries the time to file is much shorter:

Norway - 5 months
USA - 4 months
France - 5 months
Spain - 6 months

Coming to the end of another 'mad month' I can say that it is really not worth waiting. The number is sighs of relief I hear on the telephone or emails with comments such as "what a lovely surprise !", " a refund ?" , "I wish I had done this sooner"..... these all tell me that 9 months of fretting is really not worthwhile.

.....it could turn out that HMRC have been holding onto your money without good reason.