Dunwerkin, weekly in The Times, a �Feedback' column responds to readers' complaints. On March 10th 2007, one reader had written (abbreviated)...
"I am writing to highlight the increasing incorrect use of collective nouns with plural verbs...'the team are doing this' or �England are doing that'..."
The editor responded...
"Actually it isn't incorrect. To quote Gowers: �In using collective words or nouns of multitude (department, government, committee and the like), there is no rule; either a singular or a plural verb may be used.'"
The Gowers referred to was Sir Ernest Gowers, the author of The Complete Plain Words. His words are echoed by those of the editor of Fowler's Modern English Usage, who expresses the selfsame thought as, "In British English, collective nouns may be correctly followed by either a singular or a plural verb."
These two publications have long been regarded as �bibles' of current English usage. Despite that, every now and then, someone comes along and complains about something which is totally correct!
We are free to write, "The jury retires to consider its verdict today" or "The jury retire to consider their verdict today." No one in his right mind would say, "The committee leaves its hats in the hall", though that's what the singular-verb brigade must logically demand.
Believe me...the choice of singular/plural agreement is up to the individual...everyone who actually knows says so!
'Comprise of'' has been in use for well over a century. I agree that it doesn't sound right, but it looks as if it's here to stay.
'Innit' is just really an abbreviation of 'isn't it' which is itself an abbreviation.
Usage is king and it probably won't be too long before 'could of'' in place of 'could've' becomes acceptable. too, however much purists (pedants?) might complain.