Cornwall Cabinet member Lance Kennedy has resigned from the Conservative Party a and crossed the floor to join the Independent group on the council.
The Bodmin East councillor said he could no longer support the party after it joined with the Liberal Democrats to force through last Tuesday's budget which will see 135 council jobs axed.
He said he was appalled to see councillors laughing and cheering at the budget result at the same time as staff were in tears at the prospect of losing their jobs.
Mr Kennedy's defection to the Independents follows that of fellow Cabinet member and former Tory Carolyn Rule from Mullion, and means the Independents now hold the majority on the decisions making Cabinet.
Mr Kennedy, portfolio holder for public health and protection, said the decision of Conservative councillors to support the Liberal Democrat's amendment for a zero increase in council tax without regard to the consequences was beyond belief.
"What I witnessed on Tuesday was probably the worst example of cynical party politics I and most senior political have ever witnessed,'' he said.
"Even when told that these consequences would be the loss of approximately 135 jobs, and a serious reduction in capacity to a number of services, (Conservative) members again voted in favour of the ill-thought out and speculative Liberal democrat motion.
"The most significant behaviour that appalled me and has finalised my decision (to resign) was that some of the group laughed and cheered as they achieved their zero percent goal with no regard to the staff affected, many of whom were in tears at the prospect of losing their jobs.
"I cannot continue to be associated with a party that has chosen, even in these difficult times. to put party doctrine ahead of the people of Cornwall.''