What is a 'Swivel Servant'?

It's probably a play on words - swivel and civil sound similar in pronunciation. It can either be a form of mockery or wordplay (for example, in this song) almost as if it's taboo to say 'civil servant', or it could simply be a misheard expression, as Guffa said.

I had not heard this term before today, but my first thought was of a lazy-susan style device. After some searching, it seems I could be right, however the word swivel has been adopted as the name of a company which sells servers (not servants) hence swivel server. Swivel Servant might be a simple (incorrect) variation of Swivel server.

"swivel servant" - play on the expression "civil servant"

A person who pretends to work while lounging in his or hers taxpayer-provided swivel chair !!
Possible origin - CBC Radio - "Canadian Air Farce"- program