Percy's Big Mistake is an eighth season episode.
After being late so many times, Percy is afraid he'll be sent to the scrapyard when he overhears a conversation between his driver and the Fat Controller. After causing an accident, Percy decides to run away to avoid being scrapped. He is soon found by Thomas and the Fat Controller reveals there was no such notion of scrapping - just Percy working at the scrapyards and that afterwards, he can take the mail train for working so hard.
- Sir Topham Hatt
- Harvey (does not speak)
- Edward (cameo)
- James (cameo)
- 'Arry and Bert (cameo)
- Stock footage from James Gets a New Coat is used.
- When Percy passes through Knapford with the mail train, he bounces.
- When Percy is pulling the mail he is wearing Thomas' tired face.
- Surely, Percy's crew would've checked that the load of pipes were properly tied down before they left the docks.
- When Gordon collides with Percy's train, a thin wire can be seen to pull the first flatbed into the air.
- When the pipes fall out of Percy's trucks, you can see that a ramp was used to make them roll out.