The first official Santander branch in Tottenham Court Road, London will be launched today by Banco Santander chairman Emilio Botín.
A further 300 branches in the South East will also be renamed today, with another 700 across the UK to be completed by the end of January.
Also from today, Santander launches its Santander Zero current account, available to anyone who currently holds a mortgage with the bank or opens one. The account charges no fees even if the account is overdrawn.
Botín says: “This is a historic day for Santander as its name is firmly established on the UK high street.
“When Santander acquired Abbey in 2004, there were some who doubted we could make it a success. Today, there can be no doubts. Over the last five years we have transformed our UK business into one of the most successful banks in the country. The decision to become Santander will put us in an even stronger position the UK.”