Davies, who took on the position in the summer following the departure in January of chief marketing officer Mike Hounsell, will leave the company at Christmas.
Davies' departure means NTL's six regional offices must now run their own marketing activity and leaves the company without a central marketing chief.
It is the culmination of a process which began earlier this year when Hounsell left NTL. Next year will see a sales-led strategy, which focuses on encouraging new customers to enquire about NTL's range of TV and telephone-based services.
NTL is also pulling out of its major sponsorships, such as the shirt deals it has with Newcastle United and Glasgow giants Rangers and Celtic.