The first woman to be made Lord Chancellor in the thousand-year history of the role has been sworn into office.
Liz Truss, Conservative MP for South West Norfolk, was welcomed to her new appointment by leading members of the judiciary at a colourful ceremony at the Royal Courts of Justice in London on Thursday.
Ms Truss, 40, takes over the ancient office - which can be traced back to Anglo-Saxon times - from Michael Gove, and also replaces him as Justice Secretary.
Dressed in gold and black garb, she took her oath and pledged to respect the rule of law, defend judicial independence and ensure effective support for the courts.
The country's top judges - including Supreme Court president Lord Neuberger and Master of the Rolls Lord Dyson - were present for the proceedings in a packed, oak-panelled courtroom.
Describing the occasion as "historic", Lord Chief Justice Lord Thomas said that a "long-standing monopoly has been swept away, and it is plainly not before time".
He told Ms Truss: "You are the first female Lord Chancellor. Today is an historic occasion. It marks another step in the evolution of your great office, one that has for so long formed and continues to form the fulcrum between the judiciary and government, has served to defend and secure the due administration of justice, and maintained the rule of law.
"It is a step long - indeed very long - overdue. We are delighted that you are here today at the Royal Courts of Justice at this significant constitutional occasion at which you have taken the oaths of office."
He added: "My Lord Chancellor, it is readily apparent that you have had to date a most distinguished career which has demonstrated your greats skills and wide experience."
Ms Truss told the dozens of judges and lawyers in attendance in their traditional robes and wigs: "I am delighted to have been appointed to this role. It is a privilege and an honour for me to have been sworn in today as the first woman Lord Chancellor."
She said: "I am a great supporter of reform and modernisation throughout the courts and tribunals system, and that urgent task will be high on my agenda in the months ahead, as I know it is for senior members of the judiciary."
The mother-of-two, who was brought up in Yorkshire and studied philosophy, politics and economics at Merton College, Oxford, entered Parliament in 2010. She served as Environment Secretary from July 2014.
Previously she was deputy director at think-tank Reform and also worked in the energy and telecommunications industry for 10 years as a commercial manager and economics director. She is a qualified management accountant.
After Chris Grayling and Mr Gove, she becomes the third non-lawyer Lord Chancellor in a row.