I've scoured the internet for publishers and of course they have to be quite well known otherwise one is risking the theft of your book but I can hardly find any who accept unsolicited manuscripts. I suppose I'm trying to avoid having to hire an agent but does somebody here know any publishers who accept submissions?
Thanks a lot for the advise. I think that I have a better understanding of what my next step should be.
Your book is highly unlikely to get stolen by anybody in its current state.
Consider: publishing is an uncertain business at the best of times. Even really good books criminally undersell. At the moment, even if your book was in the top 1% of MSS which are well written enough to be published, it still needs editing, and a cover putting on it, and a marketing campaign, and all the other things publishers do.
I cannot say this enough: your book has no value. If somebody wants to make money from unpublished writers, there are far more effective ways (and many people employing them) such as charging reading fees, publishing your book but requiring you to buy copies of it, charging you to publish your book or edit it etc etc
Now, as to agents, you don't pay them up front. They take a percentage of your earnings. If you don't earn any money, neither do they. Do not pay anybody for anything up front.
You can find a list of UK agents in the Writers' and Artists' Yearbook. Some are also included on sites like Query Tracker and Agent Query, but those sites concern themselves mainly with US based folks.
There are some publishers who take unsolicited MSS from writers so if you feel confident you don't need an agent, seek these out but bear in mind you may be waiting a year or more to hear back from them.
Agents do more than just open doors to the larger publishers. They are experienced with negotiating contracts (so can get you a better deal and negotiate a better advance), they can sell foreign rights, they can sell the other rights associated with your work (such as audiobook rights, or if a company wished to option your work). Not everybody needs or wants an agent, so consider carefully whether any of those things (along with the other advantages of an agent) are valuable to you.
Maybe it would be ideal to send a submission a literary agent instead of directly to a publisher.
Thanks