An exposé by a former employee of Meta has become a bestseller despite the social media company banning the author from promoting the book.

Careless People by Sarah Wynn-Williams, a former director of global public policy at Meta’s precursor, Facebook, topped the New York Times bestseller chart and will be fourth on the Sunday Times nonfiction hardback chart this weekend.

The book “sold a staggering 1,000 hardbacks a day in the first three days on sale in the UK, despite Meta’s legal tactics to silence the book’s author”, said Joanna Prior, CEO of publisher Pan Macmillan. “This early success is a triumph against Meta’s attempt to stop the publication of this book.”

The book is fourth on the overall Amazon US chart, and 13th on the Amazon UK chart.

Last Wednesday, Meta won an emergency arbitration ruling which placed a temporary hold on Wynn-Williams promoting the book. The American Arbitration Association’s emergency arbitrator, Nicholas Gowen, said that without emergency relief, Meta would suffer “immediate and irreparable loss”. Meta argued that the memoir is prohibited under a non-disparagement agreement signed by Wynn-Williams.

The book was announced just one week before publication, meaning there was only a week-long window for pre-orders, which are normally open for months and help boost a book’s chart position.

Wynn-Williams’ memoir is her account of seven years she spent at the company. She “had become part of what reads like a diabolical cult run by emotionally stunted men babies, institutionally enabled sexual harassers and hypocritical virtue-signalling narcissists”, writes Stuart Jeffries in an Observer review.

The memoir is an “ugly, detailed portrait of one of the most powerful companies in the world”, wrote Jennifer Szalai in the New York Times. Wynn-Williams “had a front-row seat to some of Facebook’s most ignominious episodes”.

Meta has described the book as “a mix of out-of-date and previously reported claims about the company and false accusations about [its] executives”.

The emergency ruling dictated that Wynn-Williams must stop promoting the book, refrain from “amplifying any further disparaging, critical or otherwise detrimental comments”, and retract previous disparaging comments “to the extent within her control”.

It did not order any action by the publisher. “As publishers, we are committed to upholding freedom of speech and her right to tell her story,” said a spokesperson for Pan Macmillan.