Martin Sorrell has been up since 4 am. He began the day in London but is now in Lisbon, tucked away in the green room behind the main stage of Web Summit. Sorrell, an advertising legend who created WPP and now leads S4 Capital, greets me warmly. I’d interviewed him before in July 2020 over a video call at the height of the pandemic and had dropped him an email request for an interview when I heard he would be in Lisbon. Less than ten minutes later, Sorrell replied succinctly “Fine”. So, here we are. Sorrell is, he admits, re-thinking…