BT has also completed the termination of its Canadian joint venture with AT&T though AT&T Canada.
AT&T and BT announced last October that they were disbanding the international joint venture, launched in 1998, because of continued losses which, at one point, came to about £20m a week.
Former Concert customers have been split between AT&T and BT, based on their geographical location, and the two companies have signed commercial agreements to ensure that customers receive uninterrupted service, BT said.
BT now plans to use the Concert capabilities it has inherited to bring Internet protocol virtual private network managed services to 30 countries across Europe through its BT Ignite division, the company said.
In January, BT said that once Concert was fully disbanded, it would begin rolling out additional VPN services based on technologies such as Internet protocol security, multiprotocol label switching and Class of Service, as a way to prioritise and manage traffic in a network.