Orange UK and T-Mobile UK have completed the integration of their operations, forming a new company, Everything Everywhere Limited.
Everything Everywhere is set to become the largest telecom services provider in the UK.
The new company has its headquarters in Bristol and is currently undergoing a companywide re-branding, providing its 16,500 members of staff with new business cards and employee e-mail IDs.
In a statement, Tom Alexander, chief executive of Everything Everywhere, said: "The formal integration of our new company, Everything Everywhere Limited, is another major milestone and reflects the rapid progress we have made over the past nine months."
The name, Everything Everywhere, apparently derives from the company's aim to provide its customers with a wide range of services, allowing them to access everything, everywhere.
It had been previously speculated that the T-Mobile and Orange joint venture would be named T'Orange.