You can phone 0191 numbers for free via UK landline and mobile handsets only if you have inclusive minutes on your tariff, otherwise you will have pay an access charge to your provider followed by a per-minute rate which applies to all 01 and 02 geographic numbers.
Differences between 0191 numbers and freephone numbers
Although you can phone 0191 numbers for free if you have an inclusive calls package on your landline or mobile deal you will still lose these free minutes when making the call, whereas freephone numbers are completely free of charge regardless of your current balance. Furthermore these numbers are usually registered to the North-East areas of Newcastle, Durham and Sunderland as opposed to freephone numbers which are non-geographic.