So the book I'm writing may be a slightly controversial one and it would probably be a good idea to have someone with a good knowledge of the different legal issues take a look over it to be sure there would be no errors and perhaps advise of any required changes.
Is this something that a Publishing house would be able to advise me on if they were interested, would they have a legal dept I could confer with and make any necessary alterations, could an agent maybe be able to advise on such matters? Or would it be down to me to make sure it was all OK copyright etc wise?
big publishers have legal departments and will go through a really controversial book with a fine tooth comb and highlight any legal problems.
Fact-checking and copyright is normally the responsibility of the author but the editorial dept will sometimes assist with clearing permissions. I am not sure what you mean by "errors". The legal dept would only advise on what is legally dodgy from the publisher's perspective (ie they are mainly concerned with libel). If there were concerns from the legal POV that the book was not accurate, that would be serious, and the author would be required to show that they had done enough research to be reasonably sure that their claims were correct.
I'm not quite sure what kind of advice you are meaning though - when you say controversial, do you mean the facts are in contention, or that the book is potentially libellous? If the latter, this may put potential publishers off, libel lawsuits are incredibly costly and may cause a publisher to fight shy, although some publishers - like Gibson Square for eg - specialise in near-the-knuckle books.
But I think the first thing would be to get it taken on by an agent, who would then be able to advise you of what was involved. A publishing contract always includes a clause where you guarantee to the publisher that there's nothing they could be sued over (because they're jointly liable with you if anyone sues). The chief worry is libel, although a how-to book might worry about whether all the diagrams of how to re-wire your house were right, or would kill someone...
I think the Society of Authors has a leaflet on this. Certainly an agent would know what the form was. It's not uncommon for a publisher to have a book read for legal trouble, but it's expensive for the publisher, so they'd factor that into their decision about whether to buy the book or not.
Publishers do have legal departments, but the writer would be expected to sort out copyright and permissions themselves.
Just a PS, but non-fiction writers tend not to get agents because they are pitching the unwritten book directly to the publishers, and it's usually a Yes or No. If it's a No, they find some other subject to write about.
If, however, you go ahead and write it, then you could look for an agent to represent you.
I'm not sure I agree that non-fiction writers don't usually have agents - it does depend on the particular kind of non-fiction and the publisher.
Literary non-fiction, published by literary imprints, is almost always sold by an agent.
It's true that my agent, for example, has lots of non-fiction authors. I wouldn't know for sure, but I think it probably depends whether it's general non-fiction, for the general reader, where you often do, or something like cooking or how-to books, where there are fewer publishers, and it's not hard for the author, solo, to show that they can do something the publisher wants.
Yes, absolutely. I think depends where you see your book's niche.
If you think it's a HarperPerennial/Vintage/Bloomsbury/Penguin type of thing, their typical author probably does have an agent even for non-fiction.
Thorsons/Ebury/Vermilion/Hay House/academic or technical presses, maybe less so.
I'm sure there are agented authors at the latter group, and unagented ones at the former though.