Odd text messages from Smarty.

[RobertJ_1762026]

I have just received some text messages telling me that:
" It's max of GBP2.50/min to call, ........................For full deatils visit free at smarty.co.uk/roaming"

and "Oops, it looks like this service asn't covered in your plan.........................................etc.
At the time the phone was not being used and was in the UK.
I have no idea what service I was supposedly trying to use and why I should be informed of roaming charges. Last time I checked, Norfolk was not abroad! (Although I was on the beach in North Norfolk.)
Please help me to understand what is going on and if there is a problem with my account.

[SmartyTrousers]

@RobertJ_1762026 I would assume the atmospheric conditions made it possible to pick up a foreign network from your location (didn't it say 'Welcome to' followed by a country name at the start of the message, indicating where it thought you were?). The good news is that it's not possible to incur any additional charges on Smarty unless you choose to add additional credit to your account to cover these.