He's been in politics — without having been elected — for a long time.

But come the departure of Derryn Hinch from the Senate after the federal election, the so-called "preference whisperer" Glenn Druery will likely find himself looking for new work.

Glenn Druery before the Senate voting reform committee at Parliament House in Canberra 2016 Credit:Andrew Meares

Druery, who has been a staffer to Hinch and who freelances as a hired gun for minor political parties during election campaigns, is putting the finishing touches to his book.

The Preference Whisperer will be out in October, we are told.