Motorists parking in Ely's Angel Drove commuter car park are to be penalised to pay to prosecute those who dodge the daily charge.
The move, to increase parking charges at the car park by 50 pence a day to raise money to take action against the non-payers, has appalled Liberal Democrats.
They have accused the ruling Tory administration on East Cambridgeshire District Council of raising the daily car parking cost from £2.50 to £3 a day because it is seen as an "income generator".
Drivers boycotting the car park to leave their cars in the nearby Cambridge Business Park face fines of up to £60 which will be enforced by the district council.
Lib Dem Councillor Ian Allen, who sits on the council's environment and transport committee, said: "The Tories have got to raise the money somehow to be able to take action against those drivers who are not paying to park to force them into the Angel Drove car park. But this is not the right way to go about it.
"They are penalising those who have been paying by increasing their financial burden while other motorists have been legally getting away with it for months.
"Increasing the commuter car parking charge is easy money. It is seen as an income generator which will give the council the funds it needs to target the non-payers. But why should drivers who have been toeing the line now face increased charges to pay for those who have been getting away with it? There has to be a better way."
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