I have seen this numerous times.
In your case, if the wife has died, would the same two children inherit? Possibly not, if it is a second marriage.
Possibly, if the wife has not died, the wife is entitled to the whole of the half-share (income and capital) and could require the half-share to be transferred to her, but that will turn on the precise wording of the trust. Sometimes the intention is that the property passes to the estate of the spouse after the spouse’s death and there are sufficient other provisions to prevent the spouse being absolutely entitled (eg overriding powers of appointment, or similar).
In my opinion, you have to look at what the Will actually says. If the Will is clear and unambiguous in its language, I would find it difficult to say that the Will must be construed as the two children being entitled under the Will. However, if there is no objection from those who would have inherited via the actual wording, and if there is no legal way to correct matters without a detrimental tax charge (eg DofV, assignment of reversionary interest, etc), then it will be a question of whether HMRC require an application to court in order for them to accept that the “intended” position is how the Will should be construed, especially if there would be some potential tax charge. If any person who would be losing out objects, then you certainly will need to go to court.
In a very different situation, but one where it was equally clear that a mistake had occurred, we wrote to HMRC and they agreed to dispense with the need for formal court application.
New Quadrant Partners