Considering you're in the UK I'm gonna guess it was Hermes or DHL

Same thing happens in DK. Only, here the company actually claims that all those complaints from customers are made up. "Nono, we always bring the parcel to the door and try to make a delivery. All those people claiming to have seen our workers dump the slip in the mailbox without ever knocking or ringing are simply lying or misremembering. The security footage you have? Must be edited. The former postal workers describing how they had to do these things to keep up with our timetable? Liars, the lot of them. By the way, we're raising prices again, that's not a problem, right?"

There has been numerous occasions where the guy walked to my door with the slip, didn't knock or ring the door bell and walked in a manner that an individual may do if they are trying to sneak in or out of a place with creaky floor boards.

same happened to me last week while receiving a package from the mail man. I went to the post Office to get my package and filed a complaint. If Everyone does the same they have to start doing their job properly or they'll get fired.

OP my mail lands at my neighbors because my POST OFFICE is famous for hiring morons, THE PIZZA DELIVERY PEOPLE also keep trying to give my neighbors my food too

Some delivery people are just so lazy. They can't even be bothered to wait the couple minutes it takes someone to walk to the door so they just don't even bother. It's just sad.

They do that to me ALL the time! When they aren't tossing the packages over my 8ft fence that is. =|

That happens all the time at my house, just straight up lazy. Multiple times I have been sitting in my lounge room, right next to the front door, and they just put the collection slip in my letter box and piss off. I've been a courier, it isn't hard to knock on the door. FYL op, that sucks.

Reading all the comments I see that this is a delivery trend all over the world. My son says we should buy a boomerang to hunt them delivery drivers down when they sprint away.

This happens to me all the time, but mostly they are leaving the package in the truck (luckily). They also fake using the doorbell, claiming it doesn't work. Even if I show them it does, they keep claiming it doesn't work (remind you of anyone in politics?). It always ends up with me going to one of the places they drop it afterwards (can not be sure which one before I call the places), which is hard enough for me as it is (logistically challenged), and they are only open when I'm at work. Unfortunately, the postal service refuses to do anything about it. *sigh*