Video report by ITV News Correspondent Emma Murphy
A new chairwoman has been appointed for the Inquiry into Child Sexual Abuse.
Professor Alexis Jay will take over as chairwoman from Dame Lowell Goddard, Home Secretary Amber Rudd has announced.
Professor Jay, a child protection expert, will become the fourth person to lead the probe after the resignation of Dame Lowell Goddard last week.
Dame Lowell Goddard said the inquiry had struggled to shake off its "legacy of failure" and called the job a "struggle".
Dame Lowell, 67, was appointed in February 2015 to after two previous choices stood down over concerns about their links to establishment figures.
The inquiry, which is unprecedented in scale, was set up to investigate historical child sex abuse allegations against local authorities, religious organisations, the armed forces and other public and private institutions.
Professor Jay previously led an inquiry that revealed at least 1,400 children were subjected to sexual exploitation in Rotherham.
She said: "I am committed to ensuring this Inquiry does everything it has set out to do and does so with pace, with confidence and with clarity.
"Be in no doubt - the Inquiry is open for business and people are busier than ever working hard to increase momentum.
"The panel and I are determined to make progress on all parts of the Inquiry's work, including speaking to victims and survivors.
"I am determined to overcome the challenges along the way."
Prof Jay will take over as head of the inquiry having already served as a member of a four-person panel to assist the chair.
Home Secretary Amber Rudd said: "The Independent Inquiry has a vital role to play in exposing the failure of public bodies and other major organisations to prevent systematic child sexual abuse.
"I'm delighted Professor Alexis Jay has agreed to chair the Inquiry. She has a strong track record in uncovering the truth and I have no doubt she will run this independent Inquiry with vigour, compassion and courage.
"Let there be no doubt; our commitment to this Inquiry is undiminished.
Labour MP Keith Vaz, chairman of the Home Affairs select committee, said: "I am sure the Home Secretary will have noted that Professor Jay will be the first chair of the inquiry without legal or judicial qualifications.
"I hope it will be fourth time lucky, as we must not let the victims and survivors down."
How the inquiry has unfolded:
7 July 2014: Theresa May, then home secretary, set up the inquiry prompted by allegations of a cover-up of the crimes of prominent offenders such as Jimmy Savile and Cyril Smith. She appointed retired judge Elizabeth Butler-Sloss.
14 July 2014: Butler-Sloss resigns after calls she should quit over a potential conflict of interest over a family connection.
5 September 2014: Tax lawyer Dame Fiona Woolf is appointed as the new chairwoman of the inquiry.
31 October 2014: Woolf resigns after she is accused of having a “close association” with Leon Brittan.
4 February 2015: May sets up a new statutory inquiry and appoints Dame Lowell Goddard as its chairwoman.
27 November 2015: The inquiry announces its first 12 investigations and Goddard said she aims to complete the inquiry in five years.
4 August 2016: Goddard resigns, citing her career and family life, soon after being criticised for taking three months of holiday since being appointed.
11 August 2016: Professor Alexis Jay is appointed as the fourth chair of the Inquiry.