LONDON (BLOOMBERG) - British Prime Minister Boris Johnson is fighting to restore his authority after his preferred candidate lost his bid to take over the watchdog overseeing the UK's spy agencies.

Former Cabinet minister Chris Grayling was Mr Johnson's choice to head up Parliament's powerful Intelligence and Security Committee (ISC) but was defeated by Mr Julian Lewis, who launched a last-minute campaign for chairmanship of the panel.

Despite being a Tory like Mr Johnson and Mr Grayling, Mr Lewis won with the support of opposition politicians, a move seen as an act of disloyalty by the Prime Minister, who fired him from the ruling Conservative party.

The risk now for Mr Johnson is that he has lost control over an important and influential body at a sensitive time - the ISC is expected to release its long-awaited report on the extent of Russian interference in British politics within days.

Mr Lewis is no longer bound by so-called whipping arrangements that require him to follow Tory party orders and may be more outspoken in his criticism of the government as a result.

More broadly, Mr Johnson's failure to get his own man installed as ISC chair is a blow to his own political authority.

"It doesn't look good, it doesn't make the party look good and it doesn't make the government look good," Conservative MP Tobias Ellwood, who chairs the Commons defence committee, told Times Radio on Thursday (July 16).

"Right now the story is not about what the committee is scrutinising but on the make-up of the committee, and we need to move on from that."

Mr Lewis has been a Tory MP for 23 years and his expulsion from the parliamentary party is the latest example of Mr Johnson's intolerance of disloyalty in the ranks.

A sweeping reshuffle of his cabinet earlier this year saw Chancellor of the Exchequer Sajid Javid resign, and removed rivals who'd expressed dissenting views on key issues such as Brexit.

Though Mr Johnson's decision means he has one fewer MP supporting him in Parliament, the Conservatives still have a commanding majority in the House of Commons. But the episode is embarrassing for the Prime Minister, and a fresh political setback.

Mr Lewis is a former chair of the UK's Defence Select Committee and an expert on the military. He is also a vocal supporter of Brexit.

"They hate people who are independently minded and follow the evidence," Labour lawmaker Peter Kyle said on ITV's Peston, reacting to the decision by Mr Johnson to remove Mr Lewis. "That's why they're so upset."