Who is Robert the Fireman

Robert is Rose's truest friend, he is much older than her but is incredibly gentle and kind with her mental condition. She trusts him with everything and becomes very sad when he is not around. He is responsible for saving Briony's life at trial when he convinces Rose to reveal her biggest secret, that Briony was born between the 1st and 2nd of November and is, therefore, a Chime Child.