In Scotland, dry recyclables (waste paper & cardboard, glass, plastic and metal) may be collected together (so long as these waste are separate from other wastes). See here for the Waste Collector’s Obligations.
In England and Wales, whilst the original 2011 enactment of the Waste (England and Wales) Regulations explicitly allowed “co-mingled” collection, the 2012 amendment does away with that term.
This does not mean that collection must be as separate fractions (glass separated from paper etc) in all cases. Remember, the 2012 law amendment states:
“The duties …. apply where separate collection –
(a) is necessary to ensure that waste undergoes recovery operations …. and to facilitate or improve recovery; and
(b) is technically, environmentally and economically practicable.”
DEFRA has stated it will compile and issue guidance. This post will be updated once that occurs.