Marc Warner is the brother of Ben Warner, who is best buddies with Dominic Cummings. He's associated with some people such as Peter(?) Thiel, who is behind a number of controversial political campaigns for Trump. He is a data scientist and it was his company which did much of the work "harvesting" names of people who were targeted in the Vote Leave campaign, along with Cambridge Analytica. They had millions of names, which they had obtained (allegedly illegally) who had shown in interest in xenophobia, reducing immigration, anti-EU, etc. They obtained the names by trawling through social media comments, so if you happened to make a joke about foreigners or said you wanted to reduce immigration, your name was added to a list and you were then sent ads on Facebook and Twitter and as spam, etc. There were so many of them that they became subliminal. Others weren't sent the messages and didn't know they existed. Warner's company has been given a number of lucrative government contracts over the last few months. It's alleged they weren't even put out to tender.