Many thanks for the replies. It's for my Dad who has given his mobile number to car insurance companies and he's now being hassled
Unfortunately, his phone is quite old - Nokia 6230i - and he's adamant he doesn't want to change his number, and I think he's pretty reluctant to change his phone too, therefore I was hoping that there was a blocking mechanism either on the phone, SIM, or at network level, but appears not.
We're hoping to persuade him to have a new phone soon anyway as the battery reliability of his Nokia isn't great now. We're also planning on porting numbers to GiffGaff.
Are there any inexpensive, easy to use phones that can block incoming calls?
Thanks again.