Peter has to amputate the leg of a nine week-old Cockapoo puppy who suffers from a rare birth deformity with his leg being back to front.
The tense scenes as little Percy goes under the knife are in episode two of the series - which will air on April 3rd - but is one of the most dramatic yet heartwarming stories in the new series.
Peter said: "In all my years as a vet I've never seen anything like this before, It's a grossly deformed leg he can't use it at all. It's totally useless, it's completely facing the wrong way that leg, I've never seen this before.
"Even if you did an operation and turned that around, this joint is still abnormal here. There is no other option than to remove the leg. To have a deformed leg is not common thank goodness but it's always sad when you have a baby that has the rest of their life ahead of them and they have to have an operation like this.
"Leaving the leg attached would have led to painful ulcerated joints as the pup grew and started to put weight on it."
Peter, who was trained by Alf Wight aka James Herriot, used his more than 40 years of experience to make sure the operation goes smoothly.
Thankfully it all goes well and the pup wakes up and takes his first steps. Peter is cheered that Percy is able to cope and bounds along on three legs.
"He is such a character and lovable puppy that I was really hoping he would be okay. He has now got a disability but Percy isin't going to let that get in his way of a good life going forward."
After making a full recovery Percy finds a new home with a family from Suffolk. His new owner Hannah, who collects the pup with her son Griffin said: "We heard from a friend who works for Peter that there was a puppy available who was a bit different and needs a bit of extra care."
Peter says: "This puppy is very special, he's one of the nicest characters that you would meet in the dog world. Eveybody has fallen in love with him, he's very cuddly and gives lots of kisses as well.'
Later back in Suffolk, Hannah says: "He just slotted in as soon as he arrived. He's amazing he gets on with it and dosent let anything hold him back."
The Yorkshire Vet is on Thursdays at 8pm on 5.