On the RSPCA site, it says "If you make a donation to the RSPCA by SMS (short messaging service), the following terms and conditions apply:
The service is available to Vodafone, O2, Orange, 3, Virgin and T-mobile users.
You must obtain the bill payer's permission.
This service is available in England, Scotland and Wales only and costs �3.00 (inc VAT and the network operators' fees, which are on average 30-40 per cent). This will be charged to your normal phone bill or automatically deducted from your pre-pay card.
Vodafone, O2, Orange, 3, Virgin and T-mobile users will also be charged your standard message rate for each message sent.
To make a donation
Text "GIFT" to 60022
If you would like the RSPCA to keep you up to date with occasional mobile messages, text "HELP ANIMALS" to 60022
We will not store your details unless you explicitly tell us to and we will not share information with any other organisation."
It is interesting that the RSPCA mentions Scotland even though they do not operate in Scotland which appears to be misleading.