A new supermarket in Marlborough could be forced to close after a rival said its application was not considered.
Tesco's store on the Marlborough business park opened on 21 February following a campaign by residents.
But competitor Sainsbury's said its earlier application for a store should have been considered by planners.
Tesco said it was granted permission "fairly and squarely" and if a judicial review disagreed any decision would have to be made by Wiltshire Council.
A Tesco spokeswoman said if the court ruled in favour of Sainsbury's both companies would have to submit planning applications.
'Very big risk'
"For us it would be a duplicate application and Sainsbury's would present their more updated one.
"Should they go in Sainsbury's favour, we could have to close - and demolish our store if the worst came to the worst.
"As a business we've taken a very big risk, however we believe we've done everything we should have done."
The store spokeswoman said the company had been invited to open a store in Wiltshire by hundreds of local residents and the town mayor.
"We're delighted with the level of support we have in the town, and that's why we decided to build the store.
"We've created dozens of jobs for local people and given residents in Marlborough the store they asked us for," she added.
A Sainsbury's spokesman said it had submitted planning permission and then acquired a plot of land from Wiltshire Council.
"Sainsbury's asked Wiltshire Council to postpone making a decision on Tesco's application so both planning applications could be heard at the same time.
"Sainsbury's felt it had no option but to take legal action because both planning applications had to be considered by the planning committee in order for a fair assessment to be made."
A High Court hearing is due to take place later this year to determine whether Wiltshire Council's decision to give Tesco planning consent should be reconsidered.