Viacom’s U.K. and Northern and Eastern Europe boss James Currell has left the company.

Viacom International Media Networks said Currell had departed with immediate effect and it has started the process of finding a replacement. VIMN CEO, David Lynn, will oversee the U.K. business until that appointment is made.

Viacom’s U.K. business includes the MTV and Nickelodeon cable networks as well as the free-TV broadcaster Channel 5.

“James has been integral to the extraordinary growth of our operations managed out of the UK in recent years and Viacom owes him a huge debt of gratitude and thanks,” Lynn said. “He’s played a leading role in the acquisition and integration of Channel 5 and in the success our flagship pay brands have enjoyed in the UK, as well as the strengthening of our operations across Northern and Eastern Europe. I will miss him greatly when he departs.”

“I’ve had 18 fantastic years with Viacom and I’m proud to have played my part in the transformation of the operations we manage out of the U.K.,” Currell added. “I won’t be here in person, but I’ll always be tracking the progress of the people I’ve worked with at Viacom and wishing the best for the company.”