Probably worth mentioning that as of 2010 when I left the only other group protected from Pension changes were those that came from DEFRA and the major reason for that was that they are unionised. Whenever any plans for redundancies came up DEFRA was usually excluded by HR because of the hassle talking to the unions. I'm sure the same logic applied to pension changes although I suspect there were also TUPE clauses. IBM, like most bullies. tends to go for people who don't fight back.