I may be looking at this very simplistically, but by even answering the FOI you are confirming some of your senior officers have credit cards in their name. It is then not a very large step for criminals (who I do not think are targetting Councils as much as they are other easier targets with less resources to respond) to look at an organisational chart for an Council or authority (which is required as part of the Government's transparency agenda and usually on the website) to start linking the two.
For example, if your Head of Service for Adult Services has responsibility for libraries and there are credit card transactions for buying books, it is not a hard step to say "HOS Adult who is Joe/Jane Bloggs has a corporate credit card." I am not sure what your refusal to provide this information under an FOIA is going to change that fact.
I think, with the transparency agenda and the other ways to obtain the information that you seek to withhold as personal information is not sustainable under a PIT.
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