Duckworth Finn Grubb Waters has resigned the Mothercare.com account, worth about pounds 3 million.
The move throws the agency's tenure of the offline Mothercare account, which has spent only pounds 1 million over the past year, into question.
Duckworth Finn cited problems with its relationship with Mothercare.com's management staff as the reason for the decision. Michael Finn, the agency's chief executive, admitted: 'Despite our best efforts, there is an inability to get out the quality of work we could be proud of. Resigning business is not something you do lightly.'
At the time of press, Mothercare UK's marketing controller, Pat Mitchinson, said she was unaware of the move by Duckworth Finn and refused to comment further.
Duckworth Finn, which resigned the business on Tuesday afternoon, has agreed to see through work in progress. The agency won the Mothercare.com account at the end of July and created a national press and poster campaign to support the website's launch in September.
Duckworth Finn picked up the flagship Mothercare business last year without a pitch, making it Mothercare's first agency since 1996.
The media account, which was handed to Walker Media earlier this year, is thought to be unaffected by Duckworth Finn's decision.