Rachel Corp , the chief executive of storied British news producer ITN , is stepping down with immediate effect after nearly four years. Corp, whose exit has shocked colleagues, will be replaced by Ian Rumsey , the boss of ITN Productions. It means Rumsey is U-turning on his decision — announced just last month — to join rival producer Zinc Media Group. Corp will remain in the ITN building until May 22, but Rumsey will step into the CEO role without delay. Corp said she had decided after a “great deal of reflection” to “pursue new opportunities.” She has been linked to the BBC News CEO role in recent weeks following the exit of Deborah Turness last year amid the scandal over Panorama’s botched Donald Trump edit. Watch on Deadline “ITN has been a huge part of my life and career for more than three decades, and it has been a privilege to work alongside so many talented colleagues,” Corp said.…