the question tittle has started appearing in a box when i go on any sky bet/vegas/poker site. i am just worried because i've been using the site on and off for 5 years and never had this before.
what is causing it?
it says in the box "dont load(recommended)" or "load anyway"
Lots of secure pages include insecure content. Generally it will be pictures, logos etc, that are used throughout the site, so they will be hosted on an insecure server, whereas the stuff that needs to be secure (logins etc) will be hosted on the secure (https) server. It's bad(ish) practice, but it's not particularly scary. You can turn off the warning in Internet settings.