I’m curious if your company asks for references when hiring people? I’d guess they do, which makes the policy unethical and hypocritical.
It doesn't have to be the boss; it could be a co-worker. Generally written, it is hard to get, but almost always available with a phone call after hours.
Asking the person, "Would you rehire this person?" or "Would you like to work with this person?" has a 95% answer rate and says everything.
If the prospect can't connect you with a phone call to one of their co-workers, that tells us what we need to know.
In the US at the corporate level, this would be extremely unusual.
Not to mention how is it even useful? It's the easiest thing in the world to fake by passing along the phone number of a friend claiming to be a co-worker and full of effusive praise for you. It's not like most companies list the phone numbers of their employees somewhere publicly that you could verify.
Decades ago when I was a bartender, it was common practice for your "reference" to be a buddy who would pretend to be the manager at your last restaurant.
There’s a great clip of an Aussie radio show doing a prank like this. They call a random guy up and pretend that they have his number as a reference, and that he’s gonna get a call from some potential employer (who are considering g higher if the prankster). The random guy immediately agrees to say only great things about him and then the actual “reference call” is actually well done.
https://twistedsifter.com/videos/hamish-and-andy-random-job-...
I don't know of any company in the UK that would ever answer such a question, maybe a small shop that hasn't learnt better yet. Companies will provide references that always just say "this person has worked here for X years", no one would ever say anything either positive or negative.