Telecommunications company BT is in talks to acquire mobile operator EE for the sum of £12.5bn.

Originally, the telecoms giant was considering the buyout of O2 from Telefonica but it confirmed that a period of exclusivity “will last several weeks” in order to allow the necessary negotiations to be completed.

Yesterday, BT said it expects “significant synergies” after buying EE, mostly through “network and IT rationalisation, back-office consolidation and savings on procurement, marketing and sales costs.”

This puts an end to a three-week reverse auction which saw O2 owner Telefonica, rivalling joint owners of EE Deutsche Telekom and Orange, to offer BT the best deal. EE‘s considerably larger customer base and notable share of mobile spectrum sealed that deal.

Under the new acquisition, both Deutsche Telekom and Orange will receive cash as well as newly issued BT shares for their 50% stake in EE. The German telco would receive 12% of BT and the right to appoint a director, while Orange, its French counterpart, will take 4% equity.

In a statement about the takeover, BT said in a statement:

“The proposed acquisition would enable BT to accelerate its existing mobility strategy whereby customers will benefit from innovative, seamless services that combine the power of fibre broadband, wi-fi and 4G.”

This would mean BT will own the UK‘s most advanced 4G network.