Outside Britain, Barclays has interests in continental Europe, Asia, the United States, the Middle East and Africa.
ABN Amro has also expanded into emerging markets in Asia and has interests in Canada, Italy, Mexico and the United States. It has 4,500 branches in 53 countries.
The deal is expected to be concluded in the last quarter of 2007 and the new bank would be headquartered in Amsterdam, the capital of the Netherlands.