over the course of a full 12 month calender year it becomes obvious that the CIS worker is in fact earning less than a cards in worker.
A few things that 'cards in' workers get that CIS workers have to pay for themselves that cards in workers receive:
Keeping trade cards up to date, new training courses, purchase of work clothing, boots, travel time, travel allowance, holiday pay, bank holidays, employment rights, redundancy, trade union recognition.
So if the whole industry was cards in, the rates would not be as stated above or in whichever national agreement rule book you have in your hand. They would be well above and beyond
Electrician from the South East