This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

International Manual

Double Taxation applications and claims: Applicants/claimants: Estates and deceased persons: What happens if a personal representative dies

You may encounter a case where a personal representative dies before the administration of the estate has been completed. If there are surviving personal representatives they will continue the administration. However if the deceased is the sole or last surviving personal representative, the executor of their own estate will become the executor of the original estate.