IHTM40052 - Is the application for clearance premature?: full details of the estate not known
You have to make sure that you have full details of all of the assets and liabilities in an estate, including all aggregable property such as a qualifying interest in possession in settled property (IHTM16000), before giving clearance.
For example, if you receive form IHT30 for settled property at the same time as an IHT100 (IHTM10650) you should always wait for full details of the whole of the estate before issuing the certificate. Even if you are told that the assets passing under the will are wholly spouse or civil partner exempt (IHTM11032) you should wait for the grant, sight of the will and full details of the estate.
These cases require careful handling to avoid unnecessary offence to the taxpayers. A standard letter (SL 117) should be sent to the taxpayer. This explains why the certificate cannot be issued straightaway.
However, if it is clear that there can be no liability in respect of the settled property, for example, where the trust fund passes to charity, you can issue the certificate without waiting for full details of the estate to be received.