hunnyahmed, I don’t want to get into a lengthy argument with you on this. An IDP can not be used by itself. It must be issued to a holder of a valid driving license and must be used in conjunction with it.
The question, should you ask your friend, would be: Does UK authorities accept Driver License issued in Pakistan a valid legal document conferring driving privileges on the holder? IDP is based on that license. If UK does not recognize Pakistani Driver’s License, what good is a document based on it?
I don’t know of any country that recognizes Pakistani Driver’s License as a valid document extending driving privileges in their jurisdiction.