There seems to be some 0870 numbers which are now not obtainable as the alternative national numbers. I use RBS services which are on 0870 562 5555, and used to be able to use the alternatives provided, but these no longer work.
Has modern technology managed to block this use?

travellingman wrote on Oct 17^th, 2011 at 1:10pm:

Hello and welcome to SAYNOTO0870.COM.

I can't comment on this particular case as I'm not familiar with RBS' services.

In general, there are many companies that have replaced 0870 numbers with 0844 and other Business Rate covert-premium ones. This followed the changes in 2009 which saw the premiums or subsidy removed from 0870 numbers.

In some cases, the 0870 numbers remain active and answered in the same way as the new 08 numbers. Thus, they can be used as cheaper alternatives where call providers bill them the same as 01, 02 and 03 calls.

In other cases the 0870 numbers had a redirection message on giving the new 08 numbers. Organisations usually do this for a period and then turn it off permanently. It may be that this has happened here.

I don't consider them "blocked", more discontinued. If a 0870 number was blocked from receiving calls, then it's surplus to requirements as its purpose is simply to receive calls.