"Hi James, Have you got any production company addresses I could send spec scripts to? I've tried the Writersroom but would like to give my work a better chance."
Hmm, I do have some production company addresses, but nothing you couldn't get by using Google. Also, it depends what kind of scripts you're writing - are they comedy, comedy-drama, animation, children's drama? There are literally ONE BILLION production companies, whose addresses range from Death Star-like edifices of chrome and glass, to a bloke in his flat who uses his cat as a PA and script editor. Bigger doesn't mean better, by the way. Nibsy is renowned as the best in the business.
So here's a thing to do: look for a show that's along the same sort of lines as the script you've written. IMDB it, look for the production company, and the name of the producer (don't worry about the exec producer, who usually operates on a higher spiritual plane, and often can't even see writers, on so high a level do their molecules vibrate).
The producer is the person to send it to, usually via the address of the production company on their website, although double check this, as Working Title didn't update the address on their website for about a year, which caused some bewilderment last time I went for a meeting, although it did lead to a hilarious Richard Curtis-style last minute dash by taxi, which I had to share with some posh bloke whose surname was Bumme, a man with no sense of smell, and Julia Roberts. No I didn't.
DO NOT send your script to a load of people who work in the same building, thinking 'well, at least one of them will read it', as the chances are, eventually all the people will read it, mention it to each other, then realise they haven't all discovered some interesting new writer on their own (the best case scenario), and be cross.
The difficulty isn't so much in getting your script read, although if you are expecting to hear back by the end of the week you will be disappointed. Most producers are desperate to find new talent with their own individual voice, even if the first thing they try to do is try and bend that voice into some totally unsuitable new show they've devised about a nineteen thirties milliner who travels though time to solve hat-crime. The difficulty is in getting it to a producer who isn't actively evil, who likes your voice, and appreciates you can a) tell a proper story, and b) tell it in a matter that is wholly your own. And c), has some money, but I can't help with that.
Make sure you take some biscuits for Nibsy.