Yeah, it's home broadband! They drilled into the flat and ran Cat5e cables (I think 5e) direct.
http://hyperoptic.com/
£30 each per month (my housemate and I split the bill, so £60 in total). Ironically for such a connection, the router was only 2.4GHz and absolutely rubbish! So we replaced with an ASUS one. It's now a rock solid reliable connection and ludicrously quick. No throttling, no limits, no connection dropping. Just got a seedbox plugged in 24/7 via Ethernet.
We have 100/100 connection at work, so we're contemplating moving the FTP server to my place
Mind you, we didn't have fibre fitted in the building for a year (we were with Plusnet, yuck), so what a breath of fresh air.