Hi
As previously mentioned, Cumberland/Cumbria police records are kept at Carlisle archives. However, to access the information you must have permission from the police at Carleton Hall, Penrith. They have to check the records first to make sure there are no other people mentioned in your ancestors files
I started the process by e-mailing Cumbria Constabulary Penrith, through their web site. I had to badger 4 or 5 times over almost a year to get an answer. During this time I went to the archives where they checked the fils for me to determine that my ancestor was there. This helped speed things up when Cumbria Constabulary finally contacted the archives. The process took over 11 year, but I did get what I wanted in the end