Penalties for Inaccuracies: Calculating the penalty: Penalty reductions for quality of disclosure: Telling: Extent of telling
You must check the date from which these rules apply for the tax or duty you are dealing with. See CH81011 for full details.
An outline of telling is at CH82442. The extent of the telling is the third of the three points to be considered when arriving at the reduction for telling. The first is the timing, see CH82444, and the second is the nature, see CH82446.
The extent of the telling is whether everything is disclosed to us. If the person makes only a partial disclosure then a full reduction will not be due. There is an overlap here with ‘helping’, see CH82450, - a disclosure that makes no reference to the scale of an inaccuracy is not a complete disclosure.
When the person tells you about an inaccuracy in their return they must tell you all the facts at that time. If they do not, they may not receive the full reduction.
However, in a very complex case it may be difficult for the person to know the full extent of the inaccuracy when they start to tell us about it. It will still be possible for them to receive the maximum reduction for telling, but only if it was clear that the person was disclosing all they could remember at the time and made all efforts within a reasonable time to complete the telling.