Cable is three core; live (red), neutral (black), earth, where earth is a bare wire inside the overall jacket.
We have two systems of wiring.
Radials are wired with a low-value fuse or breaker at the panel, appropriate to what's connected to the circuit and the cable it's wired in. Most of Europe uses this system.
The UK has fused plugs throughout, so you can have an appropriate fuse for each appliance, plugged into high capacity sockets. This also allows us to use our "ring main" system, which is the best way to do house wiring I've seen.
Each floor (up to a maximum floor area per ring) has a ring of heavy (2.5mm^2) cable laid in a loop, supplied by a 32A breaker. You can hang as many sockets off this as you like. Each appliance then has its own cable and fused plug, up to a max of 13A per appliance. Although there's not much call for these, you can have 3kW on a portable appliance and plug it into any socket in any house in the country. It's a good system.
Although the ring main was originally developed to save copper post-war, it's also a key part of our national passion for tea drinking. A kitchen kettle is 3kW of sheer rapid boiling power and we'd never be seen dead with that American abomination of the warm, damp, Liptons bag in a cup.
We never went for aluminium wiring. Thank goodness.
We're not allowed sockets or light switches in bathrooms. However "bathroom" literally meant a room with a bath in it, and shower rooms never came under this rule. Recently things have changed and there's now a more sensible system based on zones (is it reachable from the bath or shower ?) and sockets are permitted with some rules.
Earth leakage breakers (RCD) came in in the early '70s but weren't used widely until 1990-ish. Now all new fitments have a 100mA breaker on the main panel and individual circuits may have 30mA RCDs where useful (external sockets, kitchens, etc.) Better designed systems use split load panels, where only half the circuits share the common ground fault RCD, so that the lights and freezer don't go off if the garden pond pump springs a leak.
Yes. All cable is three core, and everything gets bonded, right down to the lampshades. There are also rules for wet rooms like kitchens where metalwork must have supplementary bonding.
I sincerely believe that UK house wiring (to current standards) is the world's best system for doing it. It's a simple system, but it's efficient on materials and the standardisation amongst appliances is a great convenience.
-- Die Gotterspammerung - Junkmail of the Gods