Whats causing this BT test page to appear?

http://62.6.38.125/index.html

That one. Basically its happened twice in a few week. I will be on the internet, click on a link and that page will appear. Im still connected, router seems fine but nothing will work (web page, xbox, ping test etc). Rebooting the router fixes it, but why would this page appear? Normally when my router dies it will not load anything, and only recently that page appears.

Nothing has changed my end, only thing i can think of is its happened since being put on 21CN.

Like i say only happened twice in a few week, but seems abit odd

Just a break in routing, or authentication, nothing to do with your actual ADSL2+ service, more the WBC network.

So is this something that only happens on WBC? Because it never happened on 20CN

Is there a cause or fault, or just one of those things?

No you can experience that page via 20cn too.

If it has only happened a couple of times, then I wouldn't worry. If it's reoccurring then yes, time to speak to your isp. It might be a BTw issue, or it might be your isp's gateway.

BT have notified us of an issue on their network at the Faraday Metro Node.
This began at 16:00 and was resolved at 16:15. During this time customers
may have experienced issues with 21CN services.

Although mine went down at 5:30pm roughly. Wonder if it was that?