Archaeological investigations have started at the Station Road West car park ahead of the construction of a new £9 million multi-storey.
The dig is a strong signal that the authority is set on its plan to build the three-floor structure with 380 spaces – despite fierce opposition to it.
Councillors and council staff have today been told that up to half the car park could be closed to allow for the work to take place.
They have been warned that it could last several weeks. A section of the brickwork floor has already been removed.
The temporary car park further up Station Road West is open, offering 108 spaces.
The archaeological investigation is a condition of the planning permission the council awarded itself during a stormy meeting at the start of April attended by 100 opponents of the scheme.
The decision to grant planning permission was met with furious outbursts from protesters.
Many argued that the authority is contradicting a policy to reduce exhaust emissions by creating a structure which encourages vehicles into an already polluted part of the city.
Dr Stephen Peckham, a University of Kent academic, hinted that campaigners may even launch a judicial review of the decision.
And writing in the Canterbury Journal, business expert Prof Richard Scase accused the council of lacking vision.
He said: “I can think of no other city or urban area in the developed world that is pursuing such an ill-conceived scheme.
“To proceed with an inner-city project of this kind is stepping back to transport policies of the 1970s rather than pursuing the forward transport thinking of the 21st century.”
He said: “The new multi-storey car park will have capacity for charging a whopping 40 vehicles at the same time from day one, with preparation baked in to expand that number as soon as demand dictates.
“It will also be fitted with the most state of the art Automatic Number Plate Recognition technology available. This will allow far more granular pricing than we’ve ever seen in council car parks, with rates tailored to residents, visitors and commuters.”