Leader of the Liberal Democrat Group Janet Battye wants the leader of Calderdale Council and the chief executive to investigate the recent parking blunder.
An administrative error will cost the Council hundreds of thousands of pounds after council bosses admitted that parking orders in Halifax town centre have been illegal since 2008.
The council has been forced to suspend all on-street parking charges after a parking ticket was successfully challenged by a member of the public.
Coun Battye said: “This should not have happened: I’m asking the Leader of the Council and the Chief Executive to investigate to see whether there is any fault in this.
“First of all the Council must find out how it happened so that it can then make sure that it doesn’t happen again.
“It’s absolutely right that the Council has come clean on this and makes recompense to people who have paid a parking charge or a fine when the Council wasn’t legally entitled to charge them.
“And then it’s got to be put right in terms of making sure that the correct Traffic Orders are in place.”