Derek Brocklehurst, 38, refused to pay the £30 on the grounds that the sign was wrong.
The blue-circle sign is supposed to state that only buses, cyclists and black cabs can use the lane - but the word 'only' was missing.
Manchester council admitted there had been a mistake and later corrected the sign.
But Mr Brocklehurst's success could now open the floodgates for other drivers to challenge fines they have already paid after being caught using the lane, outside Victoria railway station.
And the council could be faced with a bill running into hundreds of thousands of pounds after it emerged that in the four month period since the sign was first erected on December 15, a staggering 10,185 notices of prosecution have been sent out.