Do they sell these whatsits in England? I've never seen them but then I haven't looked very hard. They're electrical connectors, about the size of a finger tip. The orange levers are spring-loaded and they clamp down on the wires that you insert. They replace the older style block of connectors with screws that clamp the wires (chockablocks), at least for low-current applications. (Big thick wires still need the big blocks).
The great advantage of these ones is that they're much less fiddly, so ideal for situations where you would need three hands if you were trying to screw down the old blocks. I used a pair today when connecting up a hanging lamp. Easy peasy.
(I now learn that these are available in England and are called Wago clips)