BT is in exclusive talks with Deutsche Telekom and Orange to buy their UK mobile business, EE for £12.5bn.
The proposed acquisition would give BT ownership of one of Britain's largest mobile service providers, including EE's 4G network. EE has 24.5 million direct mobile customers.
BT has said it "expects significant synergies mainly through network and IT rationalisation, back-office consolidation and savings on procurement, marketing and sales costs".
BT says it will continue with its own plans for providing enhanced fixed-mobile converged services for businesses and consumers.
Following the transaction, Deutsche Telekom would hold a 12 percent stake in BT and would be entitled to appoint one member of the BT Board of Directors. Orange would hold a four percent stake in BT.
In addition, BT expects the deal would allow it to sell fixed-line services to those EE customers who do not currently take a service from BT, and accelerate the sale of converged fixed-mobile services to BT's existing consumer and business customers.
If a transaction is agreed, approval by BT's shareholders will be required as a condition of the purchase.