Steve Crossman, who farms in Wiltshire, was puzzled when he received a ticket saying he had been snapped by a camera in Wales.
But he was even more surprised when he realised that he was being fined for speeding in his tractor.
With a top speed of 26mph, it would take Crossman's tractor more than four hours just to cover the distance from his farm in Horningsham to Abergarwed where the offence took place.
The farmer contacted camera bosses in south Wales to protest that not only was the tractor incapable of racking up such a speed but he had never taken it over the Severn Bridge.
The Mid and South Wales Safety Camera Partnership quickly admitted that they had misread one letter in the registration plate on the film and apologised.
Crossman told BBC Wales: 'It's a good tractor, but not that good. It can just about get up to 26mph, but that's downhill, with a following wind and with no trailer on the back. There's no way it could get close to 85mph.'