In 2004 Abbey was acquired by Santander, the Spanish banking giant which has been on an acquisition spree in recent years acquiring two other UK banks Alliance & Leicester and Bradford & Bingley as well as banks in south America and Europe.

Abbey, as with the other Santander purchases, are moving onto a standardised IT platform developed by Santander. The bank said in August 2009, it will achieve savings of over £65 million from the Alliance & Leicester acquisition. Santander paid £1.26 billion for Alliance & Leicester.

Partenon is a Microsoft-centred platform built on an IBM database. Abbey is still integrating Partenon into its practices and Alliance & Leicester expect to have completed the switch over by November 2010. In March 2009 Abbey parents Santander signed a £93 million two year deal with Accenture which will see the consultancy handle the integration of Partenon into Abbey and other acquired banks.

Accenture will provide IT consulting, business process management, IT outsourcing and business process outsourcing as part of the deal.