High Quality Content by WIKIPEDIA articles! Abbey National plc was a UK-based bank and former building society, which latterly traded under the Abbey brand name. It became a wholly owned subsidiary of the Spanish Santander Group in 2004, and was combined with the savings business of the former Bradford & Bingley in January 2010 to form Santander UK plc. Before the takeover, it was a constituent of the FTSE 100 Index.