The collective action is being led by former Which? director Richard Lloyd  who claims that Google bypassed the privacy settings of Apple's Safari browser on iPhones between August 2011 and February 2012 in order to divide people into categories for advertisers.

At the opening of an expected two-day hearing in London which opened yesterday, lawyers for Lloyd's campaign group Google You Owe Us told the court information collected by Google included race, physical and mental heath, political leanings, sexuality, social class, financial, shopping habits and location data.

Hugh Tomlinson QC, representing Lloyd, said information was then "aggregated" and users were put into groups such as "football lovers" or "current affairs enthusiasts" for the targeting of advertising.

Tomlinson said the data was gathered through "clandestine tracking and collation" of browsing on the iPhone, known as the "Safari Workaround" -- an activity he said was exposed by a PhD researcher in 2012. Tomlinson said Google has already paid $39.5 million to settle claims in the US relating to the practice. Google was fined $22.5 million for the practice by the US Federal Trade Commission in 2012 and forced to pay $17 million to 37 US states. 

For some reason it was not keen to have to do the same thing in the UK.