Many people who use twin + e or surfix etc seem to think it is not important to actually terminate the earth when twisted together, no load, no power , twist is tight enough, what ever the reason. Well they clearly dont understand what actually happens when there is an earth fault and the current which flows in earth conductor during an earth fault, the temperatures etc. They also dont realise that the earth wire is the MOST IMPORTANT PART of an electrical installation, not the red wire or black wire especially when it comes to faults.
As some qualified electrician who have some idea what they are doing know that there is constantly expansion and contraction as the wire is loaded generating heat, no matter how small. When it comes to earth wires, you will only know how good the termination is when there is a fault. High fault currents create high temperatures, if the termination is not done correctly chances are that the fault will go somewhere else and not down to earth, where is is suppose to.
I also find it rather disturbing how inspectors who carry out inspection report treat the earthing as if it is not as important as they should, i can see this by the results on the COCs which, most inspectors just write 0,2 ohms or 0,02 ohms which is a clear indication that they didnt carry out thorough earth test. I have watch how some just use a buzzer and if it makes a noise they regard it as earthed. I believe a loop impedance test should be carried out at each and ever socket outlet and at light fitting with exposed metal parts, with the results recorded at each point, just imagine, that R450 coc would suddenly go to R1450 or would it, once you know what reading you should get, it is easy to just fill it in like people do with the earthing and bonding results.