A supermarket has been told it can take over the whole of Bath's Podium shopping centre.
Bath and North East Somerset Council decided that Waitrose would not need planning permission because the space would still be used for retail.
A spokesman for the supermarket said it was still exploring its options for the future.
But some retailers in the centre said they were concerned they may only have a month to find new premises.
A spokesman for Waitrose said: "We are keen to build on 21 years of trading in Bath, however our store is no longer meeting current day demands and our lease expires in four years time.
"The application has been helpful in determining what the requirements would be in the event we were to develop our store as part of the landlord's aspirations for the shopping centre.
"We will now continue to explore all our options with the landlord in order to establish a proposal, which can be beneficial to both the city and our customers."
The shops in the centre rent their space from a landlord in London called O & H Properties.
Some have one-month contracts while others last for three months.
Mary Dawson, who runs a children's clothes shop in the centre, said: "In the short term it would just be nice to have some idea of when they felt they were going to start and when they thought Waitrose might take it all over and when they thought we were going to be given notice.
"One month or three months, whichever it turns out to be, is not very long to move your business."
A spokesman for O & H said no deal had yet been agreed with the supermarket.