I do as IWAF does and put Type 1 and 2 plastics in my green box too.

The answer is, of course, that they have to cater for the lowest common denomination and the patronising council plainly feel (I'll bet the "consulted extensively") that people wouldn't understand how to look for the little number in the triangle - or they can't be bothered to explain.

Similarly, they ban shredded paper, because, I suspect, it makes too much mess. If only people could be bothered, as we do, to bag it in another paper bag (shopping at Primark can be useful!), then no problemo!