Ashurst, Clifford Chance and the bank's long-term adviser Slaughter and May have won places on the City section of what is Abbey's first ever formal panel.
Abbey has appointed 10 more firms (see box) to its specialist and regional divisions. A spokesperson for the bank said the divisions were intended for "internal guidance", and theoretically any firm could be instructed on any aspect of UK work.
Grupo Santander often operates devolved procurement and a spokesperson said there were no plans to integrate Abbey's procurement into that of the group.
However, a panel place will provide exposure to a global financial services organisation whose European retail banking division turned over e1.76bn (£1.21bn) in 2003.
Unusually, Abbey kicked off the panel review process in the midst of the Santander takeover. It also reviewed its in-house legal function last year, cutting staff numbers from around 90 to 50.
Ashurst, Clifford Chance, Eversheds and Freshfields had few close links with the bank previously.
Clifford Chance advised Lloyds TSB on its failed attempt to take over Abbey in 2001, which could have counted against it, although it did advise Banco Santander on its successful attempt to capture Abbey last year. Ashurst is on panels for Barclays and Lloyds TSB, but has been trying to develop its corporate banking connections.
The regional panel consists of just DLA and Eversheds. The bank has relationships with Addleshaw Goddard and Hammonds, although it is unclear whether they pitched.
The law firms declined to comment.
External advisers on abbey's legal panels
City panel Ashurst, Clifford Chance, Slaughter and May