Nationwide Building Society
Nationwide uses GPT-4 to draft customer letters and cuts response times to 10-15 minutes
Nationwide Building Society uses GPT-4 on Azure OpenAI to help staff draft letters answering customer queries, with a person reviewing every output. Microsoft reports that average response times fell from 45 to 10-15 minutes, an efficiency improvement of around 66%.
Key figures
Copied exactly from the sources. Copy any figure with its citation.
from 45 to 10-15 minutes
Average response time for customer queries1
around 66%
Efficiency improvement1
What it took
Cost, team size and timeline were not disclosed in the sources.
The problem
Nationwide needed to answer customer queries faster, including by writing letters, and wanted to leave people more time for harder customer cases.
What they built
A drafting aid that uses GPT-4 through Azure OpenAI, Microsoft's hosted version of OpenAI's models, to help generate customer letters. Nationwide's chief data and analytics officer calls it the society's first generative AI solution with Microsoft.
How they did it
Nationwide had already moved its large data estate onto Microsoft Azure. It works under a "copilot, not autopilot" principle: a human reviews all generative AI output first. It has a responsible AI framework and an AI council, and receives support from IBM Consulting for an AI centre of expertise.
Results
Microsoft reports that average response times fell from 45 to 10-15 minutes, an efficiency improvement of around 66%. IT Pro repeats the same figures. Neither gives the method.
Lessons for your project
Keep a person in the loop. Nationwide reviews all generative AI output before it reaches a customer.
Start with a drafting task that staff already do. Letters are routine, so a draft is easy for a person to check and edit.
Consolidate data first. Nationwide credits its earlier move of data onto one cloud platform for how fast it could build.
Frame the tool as help for staff, not a replacement. Nationwide says it aims to free people for more complex customer cases.
Caveats
- The figures come from a Microsoft story about its customer. The method and baseline for the response times are not stated.
- The sources do not give a go-live date. deployedDate uses the date of Microsoft's story, which is an announcement date.
- IT Pro (28 May 2025) repeats the 45 to 10-15 minute figures and attributes the 66% calculation to Nationwide. It follows the Microsoft story closely and reads as relaying the same account, so it is not treated as independent confirmation.
- Nationwide's chief data and analytics officer calls this its first generative AI solution with Microsoft. Other uses are only described as planned or early.
Sources
- 'Copilot, not autopilot': How Nationwide is boosting award-winning customer service with data and AI
Microsoft UK Stories · 2025-01-21 · Vendor case study · ukstories.microsoft.com
- 'Using generative AI as a copilot is the sweet spot': A look at Nationwide's AI approach
IT Pro · 2025-05-28 · News · itpro.com
Summarized in our own words from the sources above. Spotted an error? See corrections.