The Office for National Statistics publishes Civil Service employment statistics every quarter in the Public Sector Employment First Release. The latest statistics published are for Q4 (December) 2007. Table 6 of the publication provides a breakdown of employment by Government Department. This has been available since Q1 2006 and from Q4 2006 included a breakdown of permanent and temporary/casual employees.
The detailed information requested could be provided only at disproportionate cost.