However some manufacturers strive for a zero-failure rate and test each tank as part of their quality program.

The PRA approach to supervision will not seek to operate a "zero-failure" regime.

What we see in the incident is what we call 'zero-failure tolerance'," Mr Sgobba said. "

Further, JP Morgan Fleming Asset Management was impressed with the eClient's zero-failure rate, since their previous experience with clones produced an intolerable failure rate.

But the wider message from the report is that the FSA does not try to run a zero-failure City and that the Rock implosion and run would probably have occurred even if the FSA had been operating as it would have liked.