Vodafone, the largest mobile phone operator in the world, is considering making a bid approach for T-Mobile UK, which has, reportedly, been placed on the market.
Deutsche Telekom, T-Mobile's parent company has appointed JPMorgan to assess options for the underperforming UK business.
It has been estimated that T-Mobile's value is between £2.5bn and £3.4bn.
Vodafone has a market share of 25%, if it buys T-Mobile this will increase to 40%. O2 has a market share of 27% and is currently the biggest UK mobile phone operator. Orange has 22% and 3 owns 8% of the market.
The deal would see the newly combined company with about half of the UK market, or 35 million subscribers.
A deal, be it an outright sale or joint venture, will have to be approved by Ofcom, the industry regulator.
Vodafone's new chief executive, who joined last summer, has been on the look out for acquisitions in order to consolidate in the UK market. Mobile phone operator 3, has also been seen as a potential target.