Until the summer of 2019, the Information Commissioner’s Office (ICO), the UK’s privacy regulator, had not been particularly pro-active in enforcing the law on data protection in respect of the use of cookies and programmatic advertising based on real-time bidding (RTB).

This all changed in June and July of this year, when the ICO published respectively a detailed report into RTB practices and an updated guidance note on the use of cookies. There are some key points...