The pitch was overseen by former BT Retail consumer managing director Angus Porter, who was snapped up by the bank in June to take the top marketing job of customer propositions director, a board-level position.
The appointment of TBWA\GGT brings to an end the bank's overhaul of its marketing strategy.
Porter said: "Financial services communication is changing rapidly. The model of shouting loudly, trying desperately to be heard by consumers in a noisy competitive marketplace, is outdated and inefficient. A new approach that challenges perceptions is needed in keeping with our new strategy. We want to take the junk out of mail. The appointment of TBWA\GGT is the final piece in completing a winning team that can really deliver the goods."
Omnicom Group-owned TBWA\GGT joins its sister above-the-line agency, TBWA\London, on the bank's roster alongside media agency MindShare, owned by the WPP Group.
TBWA\GGT planning director Richard Madden said: "Most banks don't really do direct marketing. They do direct sales. We want to elevate the role of direct communications. It's not just an efficient means of shifting commodity products. It's the best system for understanding and meeting customers' needs -- and so building shareholder value one customer at a time."
TBWA\GGT replaces Cheltenham-based TDA and Iceberg as Abbey's below-the-line agency. KLP Euro RSCG has worked on the account, marketing its card services.
TBWA\London replaced KLP's sister agency, Euro RSCG Wnek Gosper. MindShare, along with Naked on a project-only basis, replaced Carat.
Abbey has spent £11m on direct mail over the past year. In March, it mailed 3.5m homes, according to Nielsen Media Research.
Abbey is also expected to overhaul its brand after hiring Wolff Olins to develop a new identity. Reports suggested that Abbey National is to rebrand as The Abbey.
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