Santander is a wholly owned subsidiary of the Spanish Santander Group and is the Spanish bank which has become the biggest challenger to the UK’s long-established 'big four' brands of Barclays, HSBC, Lloyds and NatWest. In 2004 it bought Abbey National, retaining the Abbey brand, then in 2008 it took advantage of the banking crisis to swallow two more of the UK’s big former building societies.
Santander first bought the branches and savings business of Bradford & Bingley, but not its mortgages, and then the entire business of Alliance & Leicester. In 2010 all the UK brands were absorbed under the Santander name, and the bank also bought over 300 branches from RBS. Santander last year had around 12% of current accounts, savings and mortgages.