The idea of paying cafés, pubs and restaurants to allow the public to use their loos has been flushed down the pan by Harrow Council.
London's Conservative Mayor Boris Johnson last week urged the capital's 33 boroughs to join the community toilet scheme to ensure that residents are never caught short.
But a spokesman for Harrow Council said: "We have no current plans to take part. It's always been our ambition to provide the best facilities for our residents so we'll continue to do that."
This means customer-only conveniences in coffee shops, fast food joints and supermarkets will remain just that, leaving shoppers to rely on the nine sets of public toilets in the borough.
Mr Johnson has said: "The community toilet scheme is a common sense and cost-effective solution to the lack of public toilets in London.
"It is also an ingenious way around the high costs normally associated with running them.
"In particular,older people and families with young children find the lack of public loos inconvenient and an incredible burden when out and about."
A spokeswoman for Starbucks, which has branches in Harrow, Pinner and Edgware, said: "We provide toilet facilities for Starbucks customers in our coffee houses and at this stage we have no plans to change this."