From any UK network*, you can compose a
SMS message offline and send it on to any email address.
Ensure the first word of the message is the email address. Then leave a space, and the rest of the message. And send it to +447973577510.
If your phone doesn't have the @ sign (or you can't find it), replace it with a #.
You can also use a fax number, in international format, and the message will be forwarded via the tpc.int email to fax gateway.
This free service is provided by Andrews and Arnold, more info at http://aa.nu/faxtext/
* or any network which lets you send messages to UK Orange.