What grade was he in exactly? My boys could hardly read words that well at 5 (Kindergarten), but the boy was nearly 6, which is good for 1st grade here - some late birthdays are still 5, most are 6. The standard here is level C by end of Kindergarten, which is basically 1 or 2 line short sentences per page. It's not until 1st grade that they are finally reading the majority of things on their own due to instruction on word/language structure. Maybe they are just ahead with that in the UK. I wonder if he took the standard exam that he had to read and comprehend all words on screen including scenarios/paragraphs.
Maybe that's why we needed common core here. To catch up with the rest of the world. I bet my kids wouldn't be reading like they are without it - it was instituted just last year. They are asked to come up with stories using specific words and to draw out pictures about it. And to explain why something is the way it is, with written words using their limited vocabulary. Practically every night with homework I'm surprised at what they're asked to do with English. And you thought the new math was interesting...