town halls have failed to recalibrate some of the 100,000 ticket machines in the uk - making it impossible for drivers to pay the exact cost of parking .
in manchester , where 240 machines are still not upgraded , motorists without old-style coins must use £ 1 and two 20p pieces for a typical £ 1.25 hour 's parking - handing the council a 15p profit .
the council also charges £ 1.85 for an hour and a half and £ 3.10 for two hours and 30 minutes .