HMRC have now confirmed to Taxation that the Steeden v Carver case means that returns delivered on Monday 4 February will not give rise to a penalty charge, although they will extend the enquiry window.
The position is that returns delivered by midnight on 1 February were considered on time.
Because the letterboxes will not have been opened over the weekend, any return hand-delivered and in the letterbox at the start of business on Monday will be treated as delivered before midnight on Friday, and therefore on time.
All returns treated as on time will suffer no penalty charge, and the enquiry window will not be extended.
However, the result of this is that taxpayers have a reasonable excuse for not submitting their return throughout Sunday 3 February, following the Steeden v Carver decision.
As a result, returns handed in later during Monday will be treated as late, and therefore subject to an extended enquiry window, but with no penalty charge.
This will also apply to hand-delivered returns in the letterbox on Tuesday 5 February when it is opened in the morning, again because it cannot be known whether it met the midnight time limit.
After this, returns are both late and subject to penalty.