The misuse of UK citizens' personal data was "rife" between Brexit campaign group Leave.EU and other businesses owned by its founder Arron Banks, according to a former Cambridge Analytica (CA) employee who worked with Mr Banks before the referendum.
Cambridge Analytica met regularly with representatives of Leave.EU, Ukip and Eldon Insurance, owned by Mr Banks, over a period of five months, according to Brittany Kaiser, CA's former business development director, in evidence submitted to the Digital, Culture, Media and Sport select committee's inquiry into fake news.
Ms Kaiser, who left CA in March after four years with the election consultants and data firm, said: "In hindsight, I now think that there is reason to believe that misuse of data was rife amongst the businesses and campaigns of Arron Banks.
"If the personal data of UK citizens who just wanted to buy car insurance was used by GoSkippy and Eldon Insurance for political purposes, as may have been the case, people clearly did not opt in for their data to be used in this way by Leave.EU.
"I have similar concerns about whether Ukip members consented to the use of their data."
Asked whether she had any knowledge of CA employees "ghosting" in and out of countries to influence elections, as suggested by former CA chief executive Alexander Nix in secret filming by Channel 4 News, Ms Kaiser laughed and replied "no, not at all".
She said: "It's incredibly shocking how far sometimes a sales pitch could go through to suggesting things that I believe are illegal or at least quite shadowy.
"I have never heard most of what was uttered on those videos ever before in any meeting that I have been a part of, nor was I aware or had any inkling that that might have been suggested when I wasn't present."
SNP MP Brendan O'Hara showed Ms Kaiser a screenshot of the CA website which claimed the company had worked in three UK elections in 15 years, to which she replied: "I don't believe any of that is true.
"It was likely put on there as sales material to back up the fact that we were worthy of being hired by the Leave.Eu campaign."
She added: "I have never pitched that to absolutely anybody and it was not on our website when I was engaged with Leave.EU.
"I have seen that before and believe it is a cached version of the website that was never live."