Just had an unsolicited call. It took me a short while to work out that it was, as the caller claimed to be calling about the expiry of a domestic appliance warranty. Whilst talking it became apparent that the caller knew nothing about my appliance or when they warranty runs out - even though he had just claimed it was about to expire. I told him that I am registered with the Telephone Preference Service and so he shouldn't be ringing. His response was that he didn't know what that was! I remembered that this line was used by the last unsolicited caller that rang. Both callers appeared to have been ringing from the UK - they had English regional accents.
Are call centres really not training their staff about this or is this just a line that they are throwing out when challenged? It seems to be a recent thing - in the past they just used to hang up when you told them.