david005500 wrote on Jun 23^rd, 2011 at 1:30pm:

Why do you ask?

Prior to 0870, so-called "national rate" numbers were 0990 (operated by BT) and 0541 (operated by Mercury Communications, now Cable & Wireless).

As part of Phoneday in April 1995 when 1s were inserted after the national trunk dialling prefix for STD codes, these non-geographic prefixes were moved into the 0870 block.

0990 became 0870 5 and 0541 became 0870 1.

See:

http://www.ofcom.org.uk/static/archive/oftel/publications/1999/consumer/qanum999...

david005500 wrote on Jun 23^rd, 2011 at 1:56pm:

Yes it could. 

I'll hang-up my anorak again.

It's rather ironic that the OLD pre Number change codes such as 0345 have almost come back with the introduction of the "03" Geographic rate numbers.

As an example if National Rail Enquiries changed it's current 0845 number to 0345 it would be - 03457 48 49 50 just 1 digit (7) different from it's pre amended number, as it used to be 0345 48 49 50