Bishop, who joined in January 2009 from Coca-Cola Enterprises, ran a six-strong legal team.
However, she has decided to leave after a review, which followed the arrival of the new chief executive Stella David, concluded that a head of legal role would be more in line with its strategic objectives than a general counsel.
In a statement the company said: “We would like to take this opportunity to thank Eva for her commitment and contribution over the last year and wish her well in the future.”
During her time at the organisation Bishop spearheaded a number of initiatives, including the creation of a virtually operated legal function with built-in RSS feeds to the knowledge database and targeted legal news to specific sectors of the business. Her team also promoted simplified documentation, notably drafting a contract with a marketing agency for the Sailor Jerry brand in the style of the product itself.
The company is to recruit externally for the role of head of legal. HR director Rosemary McGinness will take direct responsibility for the legal function in the interim.
Bishop declined to comment.