Openreach
Openreach can claim 300Mbit/s from its cabinets
Not just claim - if you are lucky enough to have had FTTP installed it delivers. I just ran a test and got 292 down/35 up - but I do pay a bit extra for that!
Gigabit would be nice of course, and I have heard tell that Openreach have pushed full-fat fibre to 1GBbps, it's just not been rolled out yet. But, to be honest, I really can't think of many homes, or even businesses that need that sort of thing on general release. Yes, a shopping centre offering free WiFi, or large office, but do we need 1Gbps to every home?