WCRS, DDB and DLKW have made the shortlist, while Bartle Bogle Hegarty, Fallon and the incumbent TBWA\London were eliminated from the review.
The pitch is being overseen by Jeremy Davies, director of brand and communications, and Catherine Woolfe, head of advertising and communications. The review is being handled by Agency Insight.
Davies worked with WCRS at his previous job at Santander-owned bank Abbey, while Woolfe worked with DDB during her time at Volkswagen.
Jobs within the brand and communications of the energy company are currently under consultation, with 19 out of 100 jobs due to be made redundant across the advertising and marketing communications, brand strategy and engagement and internal communications teams.
The media planning and buying account, handled by MediaCom, is unaffected by the review.