The pie filling is made from fatty bacon (streaky aka American style), onion and apples. Cider is added for flavour and moistness. The filling is put into a pie crust, then covered with a top crust as well. In the top, a hole is cut in the middle, and the pastry around the hole folded back to expose the insides. The pastry normally used is a shortcrust one, though some modern variations will use a flaky pastry.
A version called “Mock Fidget” uses pork sausage instead of bacon.
As of 2007, Huntingdon Fidget Pie was still not actually made in Huntingdon. 
Shropshire Fidget Pie
A version called Shropshire Fidget Pie adds potatoes.
Huntingdon Fidget Pie would have traditionally been made around harvest time when apples were available.
It is not really known how Huntingdon Fidget Pie got its name; any hope of accurately assessing its origins are pretty much all lost in time and speculation now.
It is also called “Fidget Pie” or “Fitchett Pie.”
 Fort, Matthew. Start fidgeting. Manchester: The Guardian. 17 November 2007.