Barry Blake was a COLA, and retained his powers at the end of the fourth book. His ability was vanishing, but not very effectively because he was clumsy and his adenoids make a whistling sound. He was friends with Jennifer Troke. He shared a dormitory with Dax Jones and Gideon Reader in the first two books. Barry and Jennifer liked to vanish in class, and were frequently caught in the act, though Mrs Dann was always giving Barry a row more than Jennifer because, as Dax once said, she 'looked like butter wouldn't melt in her mouth'.

In the second book, Dax turned to Barry when Gideon deserts him to show Catherine Reader around Tregarren College. Barry talks to Dax whilst sitting on a stone wall, and sticks up for Dax when Spook Williams attacks him with a wild dog named Chip.

Barry wasn't willing to risk getting in trouble, he once nervously told Gideon to stop levitating a football over Dax's head in case it fell and he got hurt, in which case both Barry and Gideon would be given a row.

Barry was also the first person to notice Dax's resistance to glamour in the form of illusions.

He was described as tall, a little podgy, with dark hair and grey eyes.

He became good friends with Clive during Dowsing the Dead.