British Prime Minister David Cameron suffered a blow on Saturday as Mark Reckless defected to UKIP, the second Conservative backbencher to join the eurosceptic party in two months.

Reckless’s announcement was greeted with rapture at the United Kingdom Independence Party’s annual conference, where delegates jumped out of their seats cheering the switch.

The defection comes just one month after fellow Conservative backbencher Douglas Carswell also left Cameron’s centre-right party for the anti-European Union, anti-immigration UKIP.

“The leadership of the Conservative Party is part of the problem that is holding our country back,” said Reckless, who has made a name for himself as one of the Conservatives’ most rebellious lawmakers.

“Today I am leaving the Conservative Party and joining UKIP,” said the 43-year-old, sparking jubilation at the conference in Doncaster, northern England.

“These decisions are never easy. Mine certainly has not been. Many have been the sleepless nights when I have talked it over with my wife and thought about the future of our children.

“It is a decision I make from optimism, a decision that is born of belief that Britain can be better and of my knowledge of how the Westminster parties hold us back — but also of my belief in the fresh start UKIP offers.

“We all know the problem of British politics. People feel disconnected from Westminster. But disconnected is too mild a word. People feel ignored, taken for granted, over-taxed, over-regulated, ripped off and lied to.”

Reckless represents Rochester and Strood, in Kent, southeast England.

UKIP topped the polls at the European Parliament elections in May.