Neighbours scream at kids constantly - what to do?

Hi - me and husband live on an end of terrace house. The house joining ours is a couple and 4 kids (if I’m guessing I’d say the oldest 3 are between 7-12, and then a baby they had last year). We’ve lived here 3 years and only really said the occasional “hi” - they don’t really seem to leave the house much. Everyday, we can hear them screaming at the kids. In the morning before school, and then when they get back. I’ve also heard the mum scream at the baby, which was quite upsetting to hear. Now, it’s annoying but the noise doesn’t really bother me, it’s the actual content. They are constantly telling these poor kids that (and I quote) “if you don’t shut the f up, the police will take you away”, “you are a horrible f-ing girl and so is your sister”, “get the f out of my sight”. It is mainly the mum, and she just screams and screams ( we are not talking like the occasional remark, it’s every morning, every evening). I grew up in a single parent household and my mum was absolutely no nonsense, old school, so I don’t feel I’m being precious, this is just next level. I worry for the kids, and what a stressful and sad environment it is. I can’t talk to the parents - we are a professional couple with no kids and I just know it would go down horrendously. But what can I do, if anything?! I’m scared of reporting to social services in case they know it was us (almost certainly they would) and they make life difficult. But equally, I want to do the right thing for the kids.