I couldn't comment on 'Mainframe Consultants' but job security in Accenture, as in the case of most consultancies is extremely variable depending on your performance and business unit. Good performers will survive most culls (duh) whereas average and below will probably not last long, esp in harsher times. Regarding business unit/practices, I have seen a number of consultants in units such as FS being made redundant in Acn.. (this was pre the downturn)