There are some terrible scum out there who will take advantage of this awful situation.
HMRC have put put a warning about it here
Although this relates to texts and emails, they are obviously going for calls now!!
*The Game Is On*
But very annoying where a medical practice calls you from a "Number withheld" line - hospital switchboards too are often programmed this way.
The NHS telecoms contracts admins should make this fix a priority, at least to transmit a base CLI that matches the main hospital number or a centralised number.
GP practices should tell their telecoms provider the same thing.
Withholding a number is not the best way to mask the direct extension number of individual GP's or Practice Nurse's desk phone details.