Lancaster will be replaced by Nick Collard, who will assume the role of marketing and operations director on Monday 16 April. The role will see him oversee marketing and trade planning, format, merchandising and space, pricing and promotions, customer service and insight.
In September, Lancaster's remit was extended to encompass price and promotions across all store formats. He was also given responsibility for handling the retailer's look and feel from a customer-experience perspective.
Collard is currently commercial director for ambient grocery and will continue to report into commercial director Richard Hodgson in his new job.
The supermarket said Lancaster "has taken the decision to leave the business to pursue and opportunity outside of Morrisons".
Day-to-day marketing operations are handled by Rebecca Singleton with her responsibilities including advertising, in-store marketing, print services and local marketing.
The shakeup caused by Lancaster's departure will see Lisa Miao, commercial director of ambient and frozen, take responsibility for core food grocery, beer, wines and spirits, impulse and frozen.
Jamie Winter is becoming commercial director of chilled and all non-food business areas are being brought together under current non-food commercial director Mike Snell.
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