Plugwash, without wishing to put your nose out joint, but your understanding of the use of an Earth is inaccurate, to a degree.
Whilst it is true to say that the use of earth does provide protection against indirect contact, it also does many other rather useful things too, like:
Providing a path for the creation of a short-circuit when cables are damaged in a way which does not completley break the cable. This is the reason why the Earth core in T&E has no sheath on it. Should the cable be damaged, outer sheath and one core damaged, there is a reasonable chance of connection with the naked earth wire, this will create a short circuit path and thus result in the operation of the protective device.
Ensuring that the potential difference between the Neutral conductors of an installation and the fundermental mass of earth is reduced to the minimum level, ideally 0V but usually slightly above 0V. This is important as it prevents a person from being shocked by the neutral conductor. There are certain situations where a neutral shock is possible, but the presence of a cpc is irrelevent to this.
The cpc also ensure that all exposed conductive parts, and all extraneous conductive parts are maintained at the same potential difference as the fundermental mass of earth, thus reducing the overall risk of either form of indirect contact.
Without an earth in an installation, there would be a high probability of recieving a shock that would not operate a protective device, and thus increase the chances of a fatal shock.