Looks like Tom is being fully removed from leadership and major decision making at Monzo: https://www.altfi.com/article/6773_monzo-co-founder-tom-blomfield-steps-down-from-board-
I can’t think of a single reason why he would voluntarily step down. There’s no reason they couldn’t have created another seat for TS Anil on the board. It really feels like they want him out of the day-to-day running of the company. Based on all the recent news (omission of stock sale from company house etc etc.), this should have happened a long time ago.