Detailed information about the job performance of more than 900 employees of Regus owner IWG was accidentally published online after the shared office business conducted a review of sales staff.

A spreadsheet which lists the names and work addresses of hundreds of Regus sales managers alongside detailed reviews of their performance was made accessible to anyone using a simple Google search, The Telegraph has found.

IWG hired Applause, a mystery shopping business, to audit its sales staff through covert filming using “spy pens” fitted with miniature cameras.

Employee performance data was then published to a page on task management website Trello which had been made public, allowing the files to leak into Google search results.

The names and email addresses of hundreds of mystery shoppers were also leaked online.

The leaked documents show an expansive effort by Regus to ensure its sales staff were closing enough deals to compete with rival office space companies such as WeWork.

Training materials leaked online included a guide to covertly filming Regus employees. “The filming of the tour has to be kept secret,” the document said.

A Regus spokesman said that employees were aware they were being recorded.

IWG and Applause removed the documents after the companies were contacted by The Telegraph.