Former cabinet minister Chris Grayling has resigned from the Intelligence and Security Committee (ISC).
The ex-Transport Secretary had been set to take over the chair of the committee until a surprise coup by MP Julian Lewis in July.
Mr Grayling had received a nod of approval from the prime minister - but was beaten out to the position by Dr Lewis who had the Tory whip withdrawn shortly afterwards.
The former Transport Secretary's botched attempt to lead the committee came ahead of the publication of the long-awaited report into Russian interference in British politics.
Boris Johnson had been accused of trying to parachute an ally into the role of chairman after he delayed the publication of the report for months.
Dr Lewis was thrown out of the Conservative parliamentary party by Chief Whip Mark Spencer for mounting the stunning coup against Grayling.
The ISC wields major power as it scrutinises MI6 and GCHQ on matters of national security.
Its reports must be given final sign-off by the Prime Minister and redacted by the intelligence services.
The Russia report was given that sign-off just before last year's election but it was not published until July.
