WATCH: Leaking pen bothers King Charles III at signing

King Charles III became frustrated with a leaking pen when signing a book at Hillsborough Castle, an official residence in Northern Ireland, with Camilla, Queen Consort, remarking on how the pen was leaking.

The King has undertaken a gruelling schedule since his mother, Queen Elizabeth II, died on 8 September and has been performing ceremonial duties throughout the United Kingdom since then.