Stallholders fighting plans to demolish their north London market say it could have a huge effect on tourism.
Buck Street Market is one of five markets in Camden
London Underground (LU) wants to buy the space occupied by Buck Street Market in Camden to extend and redevelop its overcrowded Tube station.
But research commissioned by stallholders suggests 70% of visitors to the town would be less likely to make a return trip if plans go ahead.
A public inquiry into the proposal is due to start on 10 February.
LU wants to use compulsory purchase powers to buy the land on which the market, also known as The Camden Market, and the United Reformed Church stand.
Homes, shops and offices would also be built above the station, to help pay for the £130m redevelopment.
But Camden Lock (London) Ltd, which owns the market, says its demolition could have a knock-on effect for the whole area's economy.
Its survey of 526 people, conducted by polling company NOP, found more than 70% said they would be "less likely" to visit the area if the plans went ahead.
And it has employed an engineering firm to draw up alternative schemes to allow the Tube station to expand without taking the market's land.
Camden Lock spokesman Henry Lennard asked LU to reconsider its plans.
He said: "This survey proves that the loss of The Camden Market would damage Camden's community and economy far beyond the impact of our stallholders."
LU says the station is out-dated and needs to be re-developed if it is to cope with the anticipated 20% increase in passengers in the next 20 years.
The busy station, which opened in 1907, is often used as an exit-only station at weekends because it is so overcrowded.