A method of sterilising items by placing items to be sterilised into a puncture resistant sealable vapour barrier sterilisation bag, performing steam sterilisation under pressure via a conduit coupled to the bag whilst maintaining a heated compensating pressure environment around the exterior of the bag during steam sterilisation so as to reduce mechanical stress on the bag and sealing the bag at the completion of sterilisation. There is also provided a sterilisation services apparatus for sterilising the contents of a sterilisation bag including a pressure compensating compartment having a sealable door that maintains a heated compensating pressure environment around the exterior of a sterilisation bag during steam sterilisation so as to reduce mechanical stress on the bag.
