Jon Roles, 33, found the hefty notice on a broken down van he was meant to pick up in Yeovil, Somerset.
But on closer inspection the garage owner saw a snail eating the last remains of the disc.
Mr Roles’ father Steve, 70, who helps at his son’s business tried to contest the fine. It was upheld until police were sent a picture of the snail eating the tax disc.
It was very much a ‘the dog ate my homework’ moment
The elder Mr Roles said: “It’s almost unbelievable. I had a bit of a chuckle as I just couldn’t believe what I saw.
“I think snails like glue and ink so maybe that’s why it ate the disc.
“It was very much a ‘the dog ate my homework’ moment, but we still had the penalty notice to deal with.”
The garage owner’s father said he felt it was their duty to contest the fine because the van was in their care when it got the fine.
He said: “I suggested we talk to the police and we explained the situation but they weren’t too keen to see the evidence.
“They said it was still an offence as the disc was not properly displayed.”
The elder Mr Roles sent a letter to the police explaining the situation with photos of the snail eating the tax disc.
Avon and Somerset Police waived the fine and sent a reply back which said both Mr Roles could “interrogate” the offender.
The letter said: “After consideration of all the facts I have decided to excuse payment of the fixed penalty.
“Please feel free to interrogate the offender, preferably with a teaspoon of salt.
The hungry snail died after eating the tax disc. Mr Roles joked that the snail may have eaten “too much tax”.