This is the first time the division has sought just one core agency in what sources close to the pitch process have called 'the largest consumer account in the UK'.
Only BT rostered agencies are being considered for the brief. Agencies were invited to submit proposals in April and a pitch process involving four agencies is believed to be taking place this month.
A number of agencies are already understood to have presented.
Those selected are understood to be Fishburn Hedges, Le Fevre Communications, Band & Brown Communications and Lewis PR.
All currently handle PR for BT Retail except Lewis, whose Octane division was recently appointed to handle PR for BT Openworld, the telecoms giant's internet arm.
BT Retail head of corporate affairs Peter Willmott said: 'We are looking for one agency to carry out the core of the work with others supporting with projects - this keeps things simple. We are still yet to make a decision on which agency that will be.'
The pitch process is being handled by BT Retail PR director Jonathan Russell, who was unavailable for comment.
The decision to appoint a core agency follows a review started by Russell when he joined late last year (PRWeek, 16 November).
Other rostered agencies that work for BT Retail are iJack, Fox Parrack Hirsch, Sinclair Mason and Bite Communications.
BT Retail has around 20m customers representing three-quarters of the UK voice market. It generates around £12bn in annual revenue and employs 50,000 staff.
Last year BT Retail simplified its structure to become a more 'customer-focused' firm under the guidance of CEO Pierre Danon.
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