The position has been set out in its latest Tax Bulletin. No penalty will be charged if the returns are received in the post, or by hand, at any time on Tuesday February 1, or if they are in the post box of the Tax Office by 7.30am on Wednesday February 2.
Officially, a £100 penalty is still due when a return is not filed by midnight on January 31, but the Revenue said in practice it is very difficult to identify whether a return was delivered before or after midnight.
A return received by hand on February 1 will be late and potentially liable to the penalty, but there will be deemed to be a reasonable excuse during the period of default and no penalty will be charged.
The same applies, added the Revenue, for returns sitting in the post box at 7.30am on February 2. Thereafter, a penalty will be charged unless a reasonable excuse can be shown.
The concession follows a court judgement.
Self-assessment tax return filing deadline today