Knesset Member Avigdor Itzchaky (Kadima) on Thursday submitted his letter of resignation to Knesset Speaker Dalia Itzik.
"This was a hard decision to make, but I promised the public that if the prime minister didn't step down – I would; and I am a man of my word," said Itzchaky.
A week ago, Itzchaky announced that he plans to resign following the final Winograd Commission report into the failures of the Second Lebanon War. Kadima's Shlomo Mula is expected to take his place as MK.
In an interview with Yedioth Ahronoth published Thursday, the resigning MK stated that Prime Minister Ehud Olmert was unfit for and undeserving of his post.
"Olmert is dangerous to Israel. He is the worst prime minister in the history of the State of Israel," he stated.
Itzchaky is one of the founders of the Kadima movement and was considered a close associate of former Prime Minister Ariel Sharon. After forming the government following the March 2006 elections, Olmert appointed him chairman of the Kadima faction and the coalition.
Following the release of the interim Winograd report, Itzchaky attempted to replace Olmert with another candidate from Kadima.
"The prime minister's greatest problem is his cynicism, euphoria and charlatanry," he said Thursday.
According to Itzchaky, most of the members of Kadima say in private talks that Olmert cannot stay in office, but prefer to keep silent because "Olmert has bought them with appointments and authority."
MK Itzchaky added that he had held meetings with Labor Chairman Ehud Barak and Likud Chairman Benjamin Netanyahu over the past few weeks in a bid to bring Olmert down.
Itzchaky is considered an associate of Foreign Minister Tzipi Livni and has said in the past that she was the best candidate to replace Olmert. He claimed, however, that the foreign minister is morally and ethically stained "as she is serving today in the prime minister's government."