Ted Cruz campaign using firm that harvested data on millions of unwitting Facebook users

Exclusive: Documents reveal donor-funded US startup embedded in Republican's campaign paid UK university academics to collect psychological profiles on potential voters

Ted Cruz's presidential campaign is using psychological data based on research spanning tens of millions of Facebook users, harvested largely without their permission, to boost his surging White House run and gain an edge over Donald Trump and other Republican rivals, the Guardian can reveal.

A little-known data company, now embedded within Cruz's campaign and indirectly financed by his primary billionaire benefactor, paid researchers at Cambridge University to gather detailed psychological profiles about the US electorate using a massive pool of mainly unwitting US Facebook users built with an online survey.