Net Neutrality is an American issue. Basically, Comcast and the other cable internet companies are pushing to be allowed to charge priority fees and to limit or expand bandwidth for various kinds of internet traffic as desired.
In practice, that has started with Comcast forcing Netflix to pay a whole lot of extra money or get all data streamed from Netflix to be clamped to the point that it kills their service. (Mind you, Comcast is already charging its customers for this bandwidth use already - the money from Netflix was just a multi-million dollar bonus.) Some other examples:
- Let's say Comcast desides to launch its own search engine. Suddenly Google and Yahoo are "unavailable".
- New! Comcast Mail! And suddenly emails set via other programs start taking a day to arrive.
- Oh, you want to stream your event live? Sure thing, but you're limited to stop-action unless you pay Comcast $5,000,000 for regular priority or $25,000,000 for priority handling
Pretty much they could offer high-speed priority to anything they want and anyone who pays them, while crippling or even blocking internet services from anyone else.
It wouldn't be an issue if internet service was competitive (like it was with dial-up), but the vast majority of internet connections in the US are via cable. I don't know how cable is set up in the UK, but here the cable network is set up so that in any given area, only one cable company provides service. Basically, legal monopolies at the municipal level.