The spat between WPP and former CEO Martin Sorrell over the future ownership of digital production company MediaMonks quickly escalated into a potential legal battle this week. The Guardian first reported late Thursday that the holding group Sorrell ran for 33 years sent a letter to his London-based law firm, Lewis Silkin, arguing that any… https://www.adweek.com/agencies/lawyers-for-wpp-and-martin-sorrell-exchange-letters-over-ex-ceos-unlawful-attempt-to-acquire-mediamonks/