Field Programmable Gate Arrays (FPGAs) are highly flexible programmable logic devices that are becoming increasingly popular for use in the safety critical domain. They have predictable performance and allow parallel processing of tasks. They are not currently being used to their full potential, in particular designs are conservative due to the perceived risk of failure, e.g. systems use replicated FPGAs which may have a large number of unused logic gates. Further, they may be avoided for very high-integrity, real-time systems.