Find out who issued the shortcode and complain to them?

How does a routine SIM card get itself a network shortcode without the co-operation (ie paid for services) of a licenced telecoms provider?

Does the same logic apply to shortcodes as applies to 07/08 non-geographic numbers? I can't work out whether it does but, for those numbers...

The special numbers are issued from a number space which is managed by Ofcon. The current list is online (currently at http://www.ofcom.org.uk/static/numbering/index.htm) and from it you can find out which licenced telecoms provider is responsible for any given number (or, hopefully, mobile shortcode, but it's not immediately obvious where they are listed).

The licenced telecoms provider hopefully won't be the company spamming you, but the licenced telecoms provider theoretically risks punishment (maybe losing its operating licence) if one of its numbers is being used outside the authorised terms, so it is in their interests to make sure their customers are not doing Bad (Possibly Prohibited) Things. Such as the ever-popular unsolicited calls to TPS-listed landlines.

The licenced telecoms provider is legally required to have a formal complaints policy.

Find out who issed the number (shortcode), give the provider a ring, tell them one of their numbers is being abused, see where it leads. If you get nowhere, make a formal complaint (they are legally required to take them seriously, ie spend time and money on them).

Best of luck. These folks are [censored].