Sleight's expected exit comes as Coca-Cola reviews 150 jobs in 38 countries. It is currently in consultation with staff over redundancies.
It is not known whether Sleight will be replaced. She has been marketing director since 2006, having previously held the same post at Allied Domecq from 2001 to 2004.
At Coca-Cola, Sleight has led the positioning of sub-brands including Powerade and Glacéau VitaminWater. Last year, UK sales of Coca-Cola, Diet Coke and Coke Zero - surpassed £1bn for the first time, according to Nielsen.
Coca-Cola is expected to make London central to its European marketing operations. The company says it aims to simplify the way it does business by being more efficient.
Coca-Cola works with Mother, VCCP, Carlson Marketing, Vizeum and M&C Saatchi Sports & Entertainment in the UK.
Coca-Cola declined to comment on individual cases.
Read how Coke's European restructure will aim to bring more consistency to the brand.