A man was arrested Tuesday on suspicion of assault after an egg was allegedly hurled towards King Charles III during a visit to a town center, police said.
Bedfordshire Police said a man in his 20s was being questioned over an alleged common assault.
Charles was meeting members of the public outside the town hall in Luton, 30 miles (46 kilometers) north of London, when the projectile was apparently thrown. He was moved to a different area by his security guards and resumed shaking hands with members of the public.
The king has traveled widely across Britain since becoming monarch on the death of his mother, Queen Elizabeth II, in September. He was due to visit several sites in Luton on Tuesday, including a transit station and a Sikh house of worship, a gurdwara.
Last month a 23-year-old man was arrested after eggs were hurled at Charles and his wife Camilla, the queen consort, during a visit to York, northern England. The man was later released on bail.