In trying to obtain a geographical number for Currys 08445 616263, I found two alternative numbers in the listing.
These were  0116 289 7265   and   0116 289 0998
For both numbers, a recorded message stated, "the number you have given is not recognised".

I am wondering, at what stage in the communication system does this block cut in to prevent the call connecting?

Regards, Snowballpals.

Snowballpals wrote on Jan 10^th, 2009 at 11:48am:

In trying to obtain a geographical number for Currys 08445 616263, I found two alternative numbers in the listing. These were  0116 289 7265   and   0116 289 0998 For both numbers, a recorded message stated, "the number you have given is not recognised". I am wondering, at what stage in the communication system does this block cut in to prevent the call connecting?

From what you say, the number is not blocked, but not recognised. That is, it is now out of service so what used to be working numbers for Currys have now been changed or discontinued/disconnected.