Claims and time limits: claims by people other than the personal representatives
Where the personal representatives do not make a claim to transfer unused nil rate band (IHTM43007), any other person liable for tax may make a claim within such later period as an officer of Revenue & Customs may allow, IHTA84/S8B(1)(b).
This means that the trustees of a trust that is liable to Inheritance Tax (IHT) following the death of the life tenant, or the donee of a gift that exceeds the single nil rate band, cannot make a claim until the two year period has passed. In practice, though, where there is no need to take out a grant in the UK, so that no personal representatives will be appointed, you may provisionally accept a claim by trustees (or other liable people) within the two year period and calculate the tax accordingly.
You can also allow a provisional claim by other liable persons where the personal representatives do not make a claim because there is no benefit to the estate passing on death. For example, where lifetime gifts exceed double the nil rate band.
Where a provisional claim is made by other liable persons, you do not need to keep the case open for them to resubmit the claim at the end of the two year period. If the liable persons submit form IHT30 for formal clearance, you can issue the certificate, but you should draw the taxpayers attention to the provisions of IHTA84/S239(4)(aa).