A surgical instrument for use by an operator in a surgical procedure, said surgical instrument comprising: an interface operable by the operator in a step of operation of said surgical instrument, wherein said interface comprises a control; and an indicator system, comprising: an indicator associated with said control; a processor; and a memory coupled to said processor to store program instructions, characterised in that the program instructions when executed from said memory cause said processor to toggle said indicator between a first indicator configuration and a second indicator configuration, wherein said processor is configured to set said indicator to said first indicator configuration if said control is available for use by the operator in said step, and wherein said processor is configured to set said indicator to said second indicator configuration if said control is unavailable for use by the operator in said step; wherein said program instructions, when executed from said memory, cause said processor to set said indicator to said first indicator configuration if said control is available for use by the operator as a standard control for completion of said step; and wherein said program instructions, when executed from said memory, cause said processor to set said indicator to a third indicator configuration if said control is available for use by the operator as a non-standard control during said step. an interface operable by the operator in a step of operation of said surgical instrument, wherein said interface comprises a control; and an indicator system, comprising: an indicator associated with said control; a processor; and a memory coupled to said processor to store program instructions, characterised in that the program instructions when executed from said memory cause said processor to toggle said indicator between a first indicator configuration and a second indicator configuration, wherein said processor is configured to set said indicator to said first indicator configuration if said control is available for use by the operator in said step, and wherein said processor is configured to set said indicator to said second indicator configuration if said control is unavailable for use by the operator in said step; an indicator associated with said control; a processor; and a memory coupled to said processor to store program instructions, characterised in that the program instructions when executed from said memory cause said processor to toggle said indicator between a first indicator configuration and a second indicator configuration, wherein said processor is configured to set said indicator to said first indicator configuration if said control is available for use by the operator in said step, and wherein said processor is configured to set said indicator to said second indicator configuration if said control is unavailable for use by the operator in said step; wherein said program instructions, when executed from said memory, cause said processor to set said indicator to said first indicator configuration if said control is available for use by the operator as a standard control for completion of said step; and wherein said program instructions, when executed from said memory, cause said processor to set said indicator to a third indicator configuration if said control is available for use by the operator as a non-standard control during said step.