Stalwart of British children's television in the 70s, 80s and 90s. He's probably still at it somewhere I should think. He presented Play School and Play Away, narrated the brilliant and seminal Trumpton, Chigley and Camberwick Green, did excellent versions of Pimpernel Petroleum and The Train to Glasgow (and probably others of similar ilk). He was on Chokablok, and now narrates Dappledown Farm. The man is an institution all by himself, and should probably get a lifetime achievement award for his contributions to children's entertainment, along with Floella Benjamin, Fred Harris, Derek Griffiths and Johnny Ball all of whom were fabulous too.
Cant's trademark is his easy, relaxed style - he looks as if he's actually enjoying himself, and he clearly related to kids very well indeed, without talking down to them or patronising them. Excellent chap.