European Union antitrust regulators said on Friday they will examine whether a joint venture between the three largest British telecoms companies on mobile payments technologies and advertising runs afoul of competition rules.

We need to make sure that competing services can keep emerging on this market, so that incentives to innovate remain and customers get the best mobile commerce services at the best cost, EU competition chief Joaquin Almunia said in a statement.

In March, Vodafone , Telefonica-owned O2 and Everything Everywhere , which is owned by Deutsche Telekom and France Telecom , submitted their plans to the European Commission and have answered questions from Brussels since then.

The four month-long investigation will seek to determine whether the mobile operators plans to work together goes too far to shape the emerging areas of mobile payments as well as mobile advertising.

(Reporting By Claire Davenport, editing by Charlie Dunmore)