The Queen was honoured for her work in literacy as she was made an honorary freeman and liveryman of the Worshipful Company of Stationers and Newspaper Makers in the City of London.
Camilla, 77, made a solemn oath to obey the master and wardens of the company.
The Queen wore a white coat dress by Fiona Clare and a Cartier brooch as she was was installed in the company.
She joins the ranks of esteemed members and former members including Rudyard Kipling, JM Barrie, Edward VIII and Harold Macmillan - as well as her own husband.
The Queen was greeted on arrival at Stationers’ Hall by Alastair King, the Lord Mayor of the City of London, and Doug Wills, the Master of the Worshipful Company of Stationers and Newspaper Makers, editor emeritus at the Standard.
During the brief installation ceremony, members lined the Queen’s route as she processed inside before being cloaked in the livery’s gown by Master Wills.
She then read a declaration from a sheet of paper, stating: “I, Camilla, do solemnly declare that I will be good and true to our Sovereign Lord King Charles, and be obedient to the master and wardens of this Company.
“That I will also keep secret all the lawful counsel of this fellowship.
“And that I will not be party or privy to any hurt or hindrance of the said company, but all such practices, counsels, and devices I will disclose to the said master and wardens of the company, and them labour to hinder and break as much as in me lies.”
After the ceremony, a trumpet fanfare sounded to mark her arrival in the main hall, where she met representatives from the Stationers’ various charities and military affiliations, which support education and rehabilitation through bookbinding.
Among those gathered to meet her was the First Sea Lord, General Sir Gwyn Jenkins.
In 1557, the company established a system, later known as the Stationers’ Register, to manage its members’ publication rights.
Early publishers, including those of William Shakespeare and John Milton, used it to protect their works.
The Queen declared the register “fascinating” as she was shown an entry documenting “the plays of William Shakespeare in ten volumes”.
She was also introduced to bookbinder Matt Stockl, chatting to him about the project to rebind the miniature classics housed in Queen Mary’s Dolls House at Windsor Castle last year to mark its 100th anniversary.
As she left, members gathered outside to wave white handkerchiefs, just as the staff at Balmoral used to do when Elizabeth II left her Scottish residence.
“We just wanted to give her a rousing goodbye,” one member said.
The Queen is known for her work in promoting literacy and is a patron of charities including BookTrust, Beanstalk and the National Literacy Trust.
The Worshipful Company of Stationers and Newspaper Makers was formed in 1403 by the union of three traders: the Scriveners, who wrote with quill and ink, the Lymners, who created colourful enhancements and book binders.
By the early 16th century, printers had joined their ranks.
The company was incorporated by Royal Charter in 1557 by Queen Mary Tudor and has represented the book trade, printers, publishers, paper makers, calligraphers and book binders for more than 600 years.
Freeman Bill Bowkett, who won an award in 2016 when editor of his school magazine, now a journalist for the Standard, said, “It was such an honour to meet Her Majesty and talk to her about the wonderful work that Shine does.
“One of the prizes of the Shine award was a workshop at the Daily Mail. The Foundation supported me through my journalism training and helped me secure work as a journalist.”
Former apprentice journalist, Abbianca Makoni, said “It was wonderful to be introduced to the Queen. I was thrilled to tell her about my journey into journalism, which began with an editorial apprenticeship made possible by the Stationers’ Company.
“Their work is a perfect example of how investing in young people can create lasting impact, as I've gone on to use the skills from the apprenticeship to build a thriving media career and I know many others who've benefited from their support can say the same.”
The Stationers’ Foundation also supports education and welfare and manages the Shine School Media Awards for secondary schools which produce pupil-led publications.
