I am currently staying briefly in Stockport. Among the vast array of historical education that the town offers, is a most refreshing feature, given the current heat wave in North-west England. That is Robinsons' Brewery. I note from their museum that one of the their pubs, at Hurdlow in Derbyshire is called the Bull I' Th' Thorn Inn.
I feel certain that @Edwin Ashworth will be able to explain that.
Of course I am supposing it means 'Bull in the thorn'. But interestingly the letter 'I' is written as a capital in the pub name.
And what might be the precise pronunciation in the Derbyshire accent?