Max Hill QC has been appointed as the government's new independent reviewer of terrorism legislation, Home Secretary Amber Rudd has announced.
Mr Hill, who successfully prosecuted the failed 21/7 bombers, takes over the role on 1 March from David Anderson QC who has held the post since 2011.
The QC said he was "very pleased" to have the opportunity in a time of "heightened concern" about terrorism.
Ms Rudd said he would bring a "wealth of experience and legal expertise".
"With the threat from terrorism continuing to evolve and diversify, it is vital we have robust oversight to ensure our counter-terrorism laws are fair, necessary and proportionate," she said.
Mr Hill said: "As a practising barrister with experience in both counter-terrorism and the rights of citizens facing allegations of serious crime, I look forward to working with participants at all levels and from all sides."
Mr Hill, who has been a QC for nine years and appeared at the inquest into the 7/7 bombings, has experience in both defending and prosecuting complex cases involving terrorism, homicide, violent crime, high value fraud and corporate crime.
As part of his role, Mr Hill will have to produce an annual report on his findings, which the government will lay before Parliament and publish, the Home Office said.
His predecessor, David Anderson, tweeted: "Congratulations to the very well-regarded @MaxHillQC, who will be @terrorwatchdog from 1 March."
The would-be 21/7 bombers targeted three London Underground trains and a bus on 21 July 2005 in an attempted repeat of the 7/7 attacks two weeks earlier - but their devices failed to explode and they were later jailed.