UK plugs are notorious for needing two, and sometimes three, different types of screwdriver to wire them. Further, the pins are likely to fall out when you open the plug. Wiring a normal UK plug is not difficult but it could be a lot easier with a few design tweaks.
Hold the plug in the palm of your hand with the pins facing you. Unscrew the cable grip screws with a Philips screwdriver. These are the two screws near the bottom of the plug. It is easier doing this at this stage than later, when the plug is in two -- or more -- parts.
Loosen the central screw with a Philips screwdriver. You may need a larger one than the one already used. When the central screw is loosened, you will be able to take the plug apart. Try to ensure the pins don’t fall out, although this is not always easy.
Run the cable under the cable grip and pull it through so you have a comfortable amount of cable to work with. Strip the end 4 cm of the cable with wire strippers, where necessary. Then strip about 1 cm of sheathing from each of the three wires inside -- blue, brown and green-yellow.
Loosen the screws on the three pins. Insert the stripped end of the blue wire into the hole in the pin marked “N” for neutral. This is on the bottom left-hand side of the plug. Tighten the screw to trap the wire in the pin.
Follow the same procedure with the brown and green-yellow wires. Connect the end of the brown wire to the “L” or live pin. This is on the bottom right-hand side of the plug. Connect the end of the green-yellow wire to the remaining pin, which is the earth.
Pull the cable gently from below the cable grip, to remove the slack. Tighten the cable grip screws. Fit the back on the plug. Tighten the central screw.
For cables with only two wires, omit the Earth connection. Simply connect the blue cable to “N” and the brown cable to “L.”
Ensure the plug has the correct fuse. See link in Resources.