Chris Grayling has resigned as a member of the intelligence and security committee six weeks after he was humiliatingly defeated in his attempt to become chair of the parliamentary watchdog. Grayling wrote to the man who beat him to the position – Julian Lewis – saying he no longer wanted to serve on the body when parliament resumes next week. There was no immediate explanation of why Grayling, a former transport and justice secretary, quit. However, a Labour source said he was “off in a sulk” and had no desire to serve as an ordinary member on the body that scrutinises Britain’s intelligence agencies. Grayling had been promised the job of chair by Boris Johnson only to fall victim in July to an ambush in which Lewis stood against him and won the nomination 5-4 with the support of Labour and SNP members. A furious Downing Street stripped the Conservative whip from Lewis, an MP since 1997, who hit back by saying that No 10 had made “an improper request” in trying to get him to support Grayling for the position. Lewis then led the publication of the long-awaited Russia report, which revealed that British government and intelligence agencies failed to conduct any proper assessment of Kremlin attempts to interfere with the 2016 Brexit referendum. Although Johnson had the right to nominate five Conservatives to the nine-member committee following the election win, it was not actually up to him to pick the chair. Instead once the prime minister and leaders of the main opposition parties put forward those who will serve on the body, that group meets to elect their head, a process designed to ensure the body’s independence. The attempt to impose Grayling was controversial even among Conservatives because of his record as a cabinet minister. As transport secretary, he presided over the collapse of Northern and Thameslink rail services and the granting of a no-deal Brexit ferry contract to a company with no ships. As justice secretary, he part-privatised the probation service and banned prisoners from receiving books from relatives, a measure that was overturned in the courts. The ISC said: “The Rt Hon Chris Grayling MP has, in accordance with the Justice and Security Act, written to the chairman of the intelligence and security committee of parliament tendering his resignation from the committee. The chairman has sent a reply.”