Lawmakers are demanding a state probe into a decision by the attorney general not to prosecute former National Security Adviser Uzi Arad over an inadvertent leak to a journalist last summer.
Attorney General Yehuda Weinstein is facing an onslaught of criticism from MKs who want to know why he has not filed charges against Arad.
One of Prime Minister Binyamin Netanyahu's closest allies, Arad was discovered to be the source of the leak in February after a probe by the Israel Security Agency (Shin Bet).
He announced his retirement that same month, and Netanyahu subsequently recommended his appointment as Ambassador to Britain.
Foreign Minister Avigdor Lieberman has opposed the appointment, however, preferring to assign a professional diplomat to the post, according to Jerusalem sources.
Knesset State Control Committee chairman Yoel Hasson, a member of the Opposition Kadima party, formally requested Wednesday that State Comptroller Micha Lindenstrauss launch an investigation based on allegations that Weinstein chose not to prosecute in exchange for Arad's resignation.
Arad immediately resigned after it was revealed that he leaked classified information to a journalist during a background briefing in July 2010.
According to a report broadcast by Channel 2 News, the leak was related to information on an upgrade in civilian nuclear cooperation between Israel and the United States.