In both the US and UK, tax is generally paid on an individual’s death by the estate and not the recipient. If the deceased was neither UK domiciled nor deemed UK domiciled, and held no UK-situs assets, then UK inheritance tax should not be applicable.
The current US federal gift and estate tax lifetime allowance is around $12,000,000. This means significant wealth can pass to a UK recipient without incurring US federal estate tax. That said, this is due to 'sunset' on...