I have unrecognised charges on my bill that my supplier says come from Channel 5

We did not operate any premium rate subscription services, and only issue premium rate messages in response to competition entries submitted. Entrants are only charged once per entry submitted. If your operator has identified a premium rate message as coming from us, it is likely we will have received a competition entry from your number. While we are always happy to investigate any charges on your account, we always recommended getting back to your operator for help identifying the shortcode issuing the charges. Our contact details can be found here.

The Phone-paid Services Authority (PSA) is the regulator for all UK premium rate services. Their website includes a number checker to identify who has sent any premium rate messages you have received, but you will need the shortcode that is issuing you with the charges. The PSA can also offer advise on unsubscribing from premium rate services and contact details for their operators.