USB wall sockets are easy to fit: they are a direct replacement for the faceplates you already have on your wall.
They come in a variety of colours and finishes, as well as in single- and double-gang (one or two mains sockets).
Before you buy USB wall sockets, first remove your current faceplate first and check the depth of the back box and buy a replacement that will fit. Most require 25mm but some are deeper than this.
Also, be sure to turn off the electricity at your consumer unit before removing the existing faceplate and installing the replacement.
LAP 13A 2-Gang SP Switched socket + 3.1A 3-Gang USB
Although you can get two-gang faceplates with four USB ports, this LAP model from ScrewFix is both well priced and well designed.
Unlike some rivals which don't include switches for the mains sockets, this does. And it locates the three USB ports between the sockets rather than above them, which means they're not blocked by certain bulky mains power supplies.
There's 3.1A of power shared across the three ports, so you can charge a tablet and two phones at the same time.
Masterplug Polished Chrome Switched Socket + 3.1A USB
Most UK homes have white plastic sockets, but if you're replacing them with USB versions, you might like to upgrade to a different style.
This Masterplug socket is finished in polished chrome and looks great. Plus, if you don't like the white inserts, there's a black option too.
It's even available in brass, nickel and white finishes too.
There's 2.1A shared between the two USB ports and they shouldn't be blocked by mains plugs.
Masterplug Double Socket with 2 USB ports (twin pack)
When you want to replace lots of sockets, this twin pack from Argos could be ideal.
It's a pretty standard white plastic affair made by British General, but puts the two USB sockets in the middle to avoid getting in the way of mains plugs.
As is expected, there's 2.1A shared between the sockets, so if you connect both a tablet and phone, charging may be slower.
For example, an iPad can use all 2.1A to charge at full speed. Plugging in a phone at the same time will mean both devices receive less power than they could otherwise use and will charge slightly slower.
LAP 13A 1-Gang SP Socket + 2.1A 2-Gang USB
Not all sockets are two-gang and if you want USB ports where there's just a single mains socket, then this one from ScrewFix will do the job.
It's switched and like others offers 2.1A across a pair of USB ports.
Bear in mind that unlike a lot of two-gang USB wall sockets, this one requires a 35mm back box, so make sure yours is deep enough.
British General Brushed Steel unswitched socket + 4.2A USB
When two USB ports simply aren't enough, this British General faceplate includes four, offering a total of 4.2A of charging power.
There's not enough room for switches, so the mains sockets can't be turned off.
This is the brushed steel version, but B&Q sells other finishes too, including a flush version - all are £20.
British General Double Socket 4 Gang USB 4.2A
For those with plainer tastes, this is the white version of the British General quad USB socket above.
You save a fiver, and you get the same quartet of USB ports with each pair sharing 2.1A of power.
As will all the British General sockets here, it supports "smart USB" which means it will go into standby mode when it detects the devices are fully charged, and also claims to "adjust the charging pattern" according to which device you connect.