It turns out that twenty people were interested enough to apply, and six to be interviewed:

http://www.whatdotheyknow.com/request/recruitment_process_for_identity

So it looks as though there were plenty of people who actually wanted this job. However, I suspect the Home Office didn’t want it done by anyone who was going to scrutinise the ID Cards scheme with any energy or enthusiasm, so anyone who actually wanted the job was (in their eyes) automatically disqualified from doing it. Hence all the applications were turned down, and Sir Joseph (who didn’t apply and wasn’t interviewed) was ‘phoned at home by his former Home Office bosses to be offered the job.