The Wall Street Journal is reporting T-Mobile owner Deutsche Telekom and Orange owner France Telecom are to combine their UK divisions.

This would create the largest mobile operator in the country, with a combined total of 30 million customers and around 38 percent of the market.

It's not clear if the deal, which the WSJ expects to be announced early Tuesday morning, will be a traditional merger or whether both brands will remain intact.

Savings could be made in terms of sharing and upgrading infrastructure, as well as rationalising retail stores, and sales and marketing efforts.

It's been known for a while that Deutsche Telekom was considering its options for T-Mobile UK, which is the smallest of the four UK networks. It wrote off €1.8 billion on the business in its first quarter financials

Details of the deal will also have to be considered by the Office of Fair Trade.