For historical reasons just about every domestic installation in the UK uses the same European standard voltage of 230V for every socket. In turn, almost all sockets used indoors are the same size and shape and deliver the same maximum current. (Some farms have three-phase 415V supply, but I don't think that's often run to the house itself...!)
Secondly, current. UK domestic power sockets are all rated at 13A, whereas in the US there's typically different sockets for different kinds of jobs. However, these sockets are joined in a "ring main" which is typically rated at 32A in total for all the sockets on the ring: so in theory connecting live and neutral on a ring main can deliver 230V * 32A = 7.3kW.
Power in the UK is distributed from the supply company's meter to a "consumer unit" (these days, RCDs and circuit breakers) from whence the ring mains for sockets, lights and heavy equipment are powered. Like sockets, breakers are double-pole. The power company generally only provides a single-phase supply from their meter, it's an offence to tinker with anything upstream of that.
Earth is typically a earth rod (TT), separate earth from the supplier (TN-S) or combined and separate from the supplier (TNC-S) combined with separate connections to the water main (if it's metal) and the gas main.
Most houses have two ring mains, typically upstairs and downstairs, and for convenience most have an upstairs and a downstairs lighting radial circuit. Electric cookers typically and water heaters (immersion heaters) typically get their own circuits rated at 32/40 amp and 20 amp respectively Lighting, the ring mains, and high-current circuits use different sizes of cable and m.c.b's (miniature circuit breaker).
The UK has been described as one of the most heavily fused countries on earth. As the ring main can in theory deliver 32A to the socket, each appliance has its own fuse built into the plug. That, along with the higher voltage and current, is one reason why the UK has such big plugs. These fuses are (these days) clipped into their own holder which can be (reasonably) easily extracted without taking the plug apart; they come in 3A, 5A and 13A sizes.