UK ISPs sell various different speeds including 'fibre' at the high end. However it's never true fibre and you'll have copper cable no matter the package you pick.
I had Plusnet 17MPS but in actual fact it was ~6MPS download and 0.5MPS upload. The bad part was if I did an upload of say ~20MB it would throttle my download speed thereby slowing everything to a halt.
I tethered my phone to my laptop and got 16MPS upload speeds....