Local Liberal Democrats Lorely Burt MP and Councillor Ian Hedley have written a scathing letter to Solihull Council about the controversial introduction of 'Pay-and-Display' parking machines across the borough.
Income from car parks across the borough has plummeted by £293,000, including £215,000 in Mell Square alone, since the council replaced Pay-On-Foot machines with Pay-and-Display.
Lib Dems have been campaigning against the change, arguing it would hurt local businesses, but Conservatives have defended it, blaming the drop in income on the nearby Morrison's offering free parking.
Mrs Burt said, "Parking at Morrison's has always been free for a period and this severe drop in car park income suggests what we have suspected all along: fewer shoppers are parking at Mell Square and other car parks because the Pay-and-Display machines are putting them off.
"Conservative council bosses' anti-business stance becomes farcical when you find out that their proposed solution is forcing Morrison's, a private business, to introduce car parking charges.
"I urge Conservative councillors to reconsider Pay-and-Display, which is in danger of becoming a fiasco for local shops."
Cllr Hedley said, "It seems a terrible shame that a plan to save money has led to a loss of income and possible damage to local shops.
"The Liberal Democrats have been saying from the start that Pay-and-Display would create problems.
"It's time the Conservatives on the council listened to local people instead of telling them what to do."