72Point began the partnership in May with The Flower Express, an installation of 3,000 flowers on a Heathrow Express train to celebrate RHS Chelsea Flower Show.
The agency said the campaign achieved 57 pieces of coverage with a reach of 3.68 million and a social media reach of 197,000, including coverage in The Sun, Metro, Daily Mirror and the Independent.
72Point, which is known in the industry for its PR surveys, said it created "a stand-out media moment to position Heathrow Express as a premium lifestyle brand" by aligning it with one of London’s most iconic events.
"The installation was visually stunning and completely unexpected by customers, delivering a truly unique experience that they felt they had to share on social media, leading to some of the highest social engagement Heathrow Express has ever seen," Nathan Harrison, Communications and CSR Officer at Heathrow Express, said.
72Point managing director Chris Pharo said: "Securing this contract with one of the UK’s most premium travel brands is testament to our commitment to delivering top-class creative, which communicates our partners’ values and commitment to their customers.
"Our promise of both quality and quantity, in terms of our creative and unparalleled levels of media coverage, means that this is guaranteed to be an incredibly successful partnership over the next 12 months."
