Virgin Holidays lifts email open rates 2% and generates millions in revenue with AI-written subject lines
Virgin Holidays adopted Phrasee's AI-powered natural language generation tool to write brand-compliant email subject lines, raising open rates by 2 percentage points — a gain worth several million pounds in additional revenue given the brand's 22 million annual email volume.
Background
Virgin Holidays' email marketing team struggled with slow, opinion-driven subject line creation and no systematic testing culture. With 22 million emails sent annually, even small engagement improvements carry significant revenue implications — but the team lacked the tools to test at scale.
What Was Implemented
- Adopted Phrasee's AI NLG/NLP platform for automated email subject line generation
- Fed Virgin's brand guidelines and tone-of-voice documents into Phrasee to ensure brand compliance
- Deployed in two weeks for a CRM team of five people
- Enabled rigorous multivariate testing of subject lines at a scale not previously possible
- Used machine learning feedback loop: Phrasee continuously improves based on engagement data from previously sent subject lines
Results
Email open rates increased by 2 percentage points , generating several million pounds in additional revenue (company-reported), across approximately 22 million annual emails. Subject line creation time went from weeks to minutes.
Lessons
- AI-generated subject lines that sound human and maintain brand voice can outperform human-written subject lines — not because AI is inherently more creative, but because it can test far more variations at scale
- A 2 percentage point open rate gain is modest-sounding but economically significant at high email volumes: the value of incremental opens scales linearly with list size
- Setup time of two weeks suggests AI copywriting tools have low deployment friction when brand guidelines are clearly documented
- Freeing copywriters and CRM teams from subject line iteration unlocks capacity for higher-value creative work