There was no IHT charge on the funds being paid into the trust, because that is not an occasion of charge (if done within two years of death). However, once in the bypass trust, it is relevant property, so there will be an exit charge, unless, somehow, it qualifies for some other treatment (which is unlikely).
Normally, the start date for the purposes of the ten year cycle for the funds (the “lump sum”) which come from the pension begins on the date the individual joined the pension scheme. That will have been many years before the individual’s death, in most cases. This means that you possibly have two “settlements” for IHT purposes: one comprising the £10 (or other nominal sum) which was used to establish the bypass trust and the other comprising the lump sum. It is normally best to use up the £10 asap, so that you only have one IHT settlement going forward.
Ignoring the £10, the property in the bypass trust only became relevant property when received by the trustees of the bypass trust (as Richard points out). That means that, whether you are, in fact, calculating the IHT on an exit before the first TYA or during a subsequent 10-year cycle, the calculation will need to take into account that that property only became relevant property part-way through the cycle. I found Tolley’s Inheritance Tax helpful when working through the calculations in different scenarios, in particular, how to bring later additions into account.
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