The agency won the work in September after a competitive pitch. It was previously held by M&C Saatchi, which ran the account through its fast-turnaround operation Immediate Sales Agency.
Quiet Storm said that it was quitting because it wanted to develop a longer-term commitment with Lastminute. However, a series of meetings to try and reach an agreement failed to reach a satisfactory conclusion.
There were also issues about the sum that Lastminute was paying the agency, which created the "keep weekends sacred" campaign.
Trevor Robinson, managing director and creative director at Quiet Storm, said: "I know it's unusual in the present climate to resign business, but as an agency we have moved away from project-based work with now over 90% of our clients on long-term relationships."
He said that Lastminute was a fantastic brand, and that he hoped Quiet Storm would work with the company again.
Lastminute.com is currently reviewing its £2m media account, which is held by PHD, and its PR agency, which is Biss Lancaster Euro RSCG, following the appointment of Vijay Solanki as marketing director in August.
Solanki said that Lastminute would continue to use agencies on a project basis only because reflected the nature of company. He said that working on a project basis allowed Lastminute to talk to a variety of up-and-coming creative agencies.
"For us it's business as usual. I think someone said that it's a quiet storm in a teacup," he said.
Solanki joined from Shazam, but has also worked in marketing for Capital Radio and Emap.
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