Catherine Bithell joins the newly created role from the Unite union, where she was head of media and campaigns.
Bithell's appointment follows the recent departure of external affairs director Victoria O'Byrne, who has joined schools watchdog Ofsted as head of comms (PRWeek, 7 February).
The IPPR, said to be Tony Blair's favourite think-tank, also recently lost media manager Richard Darlington and senior media officer Matt Jackson.
Darlington has joined the government-funded initiative Creative Partnerships, while Jackson has moved to the Home Office.
- Separately, PRWeek last week revealed that right-leaning think-tank Policy Exchange has lost its comms chief Steven King to APCO Worldwide (PRWeek, 30 May).