Senator Doug Finley has died after a battle with colorectal cancer.

He was 66.

His wife, Conservative cabinet minister Diane Finley, says her husband died today after “a hard and very public battle with cancer.”

Doug Finley was the organizational “pitbull” behind Prime Minister Stephen Harper’s rise to power, and built a reputation in conservative circles for mercurial temper, implacable calm, fierce loyalty and prodigious work ethic.

Finley was born in Exeter, England, but was raised in Scotland and maintained his distinctive highland growl.

He is survived by his wife, his daughter Siobhan by a previous marriage, and three grandchildren.

In a statement, Harper says Canada has lost a fine public servant, and he has lost “a dear and valued friend.”