Streets traders in Birmingham say they fear their livelihoods are at risk because of new rules the city council is introducing.
A new criteria requiring street traders to sell "innovative products" has angered traders, some who have worked in the city centre for decades.
They say they plan to pursue a judicial review over the introduction of the policy.
Birmingham City Council said it "robustly defended" its position.
The Street Trading policy, which was approved on 3 November, stated the changes were designed to create an environment that is "sensitive to the needs of the public and businesses" while providing "quality consumer choice".
It states that for traders to be given consent to operate, the "quality of goods and innovative approach" will be considered by officials, adding that "innovative products refers to goods that are not readily available within the high street".
'Soul of city'
Solicitors have written to the council setting out their opposition to the policy before taking further legal action.
In the letter, stallholders and the Birmingham Street Traders Association (BSTA) say the new rules would cause "irreparable damage to the soul of the city".
Dan Rosenberg, from solicitors Simpson Millar, said the traders sold a variety of products, from hot food such as jacket potatoes and Mexican meals, to seasonal goods like umbrellas and hats.
He said they had "been a fixture of Birmingham's streets for many years".
"Despite all of these businesses proving viable before the pandemic, there is a risk that they will be caught by the new criteria of requiring innovative products, and many are now gravely concerned about whether they will lose their pitches as part of the newly introduced annual review."
Florists and tourist souvenirs sellers Allan and Samantha Poole, from the BSTA, said they were "very sad to have reached a position where we are forced to pursue legal action," adding they felt they had "no choice".
The council said it would not comment further given the start of the legal process.