It is understood that Ennals' role as director of group customer management is being scrapped as the bank moves to split its marketing function into divisions such as marketing communications and CRM.
Some of his responsibilities will be taken on Jane Almond, currently managing director at LloydsTSB Evolvebank.
Ennals is widely credited with having successfully managed the integration of the Lloyds and TSB brands during his tenure and has since continued to manage the enlarged group's central brand strategy
His departure will put a question mark over Rainey Kelly Campbell Roalfe/Y&R's grip over the bulk of its £36m advertising account, which it picked up earlier this month after a lengthy pitch.
Ennals has occupied the top marketing position at LloydsTSB since 1996 and held a string of high-profile roles including global marketing director and chairman at Air Miles and European marketing director at Reebok, during the sports brand's heyday in the early 1990s.
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