My 5 year old is being bullied, can I take him out of school for lunch?

Hi my 5 year old son is always being punched, hit and kicked by this boy in his class, it does seem to be now they are in the big playground at lunchtime, school say they are on to it but the dinner ladies are rubbish. Can I take my son home for lunch without warning, like tomorrow when he goes back to school. ??