Sara Tate and Martin Smith join the agency from Bartle Bogle Hegarty, while Ed Warren joins from Delaney Lund Knox Warren & Partners.
The hirings follow a number of account wins at Mother, including the global Dell account and the recent Motorola appointment. The three are expected to work on the new accounts, as well as Boots, although no final allocation of duties has yet been made.
Smith, a former Campaign Face to Watch, was the senior planner on accounts including Vodafone, Woolworths and KFC at BBH. He joined the agency in 2003 from Saatchi & Saatchi. He said: "I've always been a huge fan of Mother. I think its work is brilliant, I love its work ethos and it will be lots of fun to be part of it."
Tate was the lead planner on British Airways, Smirnoff Ice and Baileys during her time at BBH. She began her career at Abbott Mead Vickers BBDO.