The energy stored in LHC magnets presents a considerable challenge for commissioning even before any beam is injected. Furthermore, the energy stored in the nominal LHC beams is such that it presents a serious threat to accelerator equipment in case of uncontrolled beam loss. Consequently the safe operation of the LHC requires the correct functioning, at all times, of several systems which together constitute a complex machine protection system. An overview of this system is presented.
