How Do You Withhold Your Telephone Number?

To block your number from people that you are calling it's *67 then dial the number you are trying to call.

The normal function with a landline phone is to dial 141 before the actual number. This will mean your number comes up as "Private" or "Withheld" to the person you are calling.

If you are calling from your mobile, you should be able to disguise your number by choosing "Hide my ID" on your handset. Obviously this function will vary from model to model - check your manual for full information on this.