Permanent Undersecretary 
(also Permanent Secretary)
noun
(In the UK) a senior civil servant who is a permanent adviser to a Secretary of State.Would you consider that she should instead invite you to dinner with her Permanent Secretary and three or four senior officials?...
- The current Permanent Secretary has already made a start: widening the pool of recruitment to bring in senior staff with a greater level of expertise.
- ‘What we want is something which the public wants, is incredibly popular and is free,’ says the Permanent Secretary.