There's two points here.
Adrian is right about the generic similarity as to the original setup, but there are a pile of little wrinkles about using them on UK roads today, if that is where you are heading.
First you have the trailer regs about weight, braking on each wheel, etc, then you have the limitations about using electric brakes in the UK now. As examples, they must work automatically ( adjustment from the drivers position isn't allowed ) and they must have a power source on board the 'trailer' that can bring it to a halt automatically if it disconnects at the wrong time, and when that power runs down it shouldn't be able to roll away again. Basically you need a small battery and an automatic controller on your 'trailer' and some provision for an effective handbrake. Absolute 'compliance' might be really tricky, but if you could demonstrate that you had an effective automatic system that was really, really close to the requirements you might get cut some slack if you get a roadside assessment. Emergency stop from 50mph behind a GMC might be - interesting.
I believe all the technicalities can all be overcome, but it is tricky. Best plan would be to get an understanding of exactly how the originals worked, then to google 'electric brakes uk' or the like and look for fora where people like the Airstream caravan groups have already tackled this for similar systems.