I don't doubt this is a difficult one to to solve, there being so many different things that could be causing the problem. The fact that it seems to occur so randomly doesn't help much either.
Nevertheless, in answer to some of the questions asked above ... I'm using HH4 on default settings. Parental controls are off. Both wired and wireless connectons are used at different times, with Windows XP Sp3 desktop, and Windows 8.1 laptop. Both are affected equally when the system goes into 'Waiting for static bbc....' or 'Waiting for static bbcimg ...' or whatever intermediary set of servers is not co-operating or perhaps temporarily overloaded.
Firefox may give contradictory messages: 'Connecting' and/or 'Connected' but the effect is not much different. In the latter case there's a white but otherwise blank page. In the former, there may be what looks like a basic version of the web page with most of the text and images missing, and links that don't work. IE 11 simply says 'Cannot connect ...' .
As has already been suggested, this isue may be more widespread than the numbe of people reporting it may indicate. My neighbour, also on BT, said, 'Yes, it happens sometimes, but I try again later and the problem has usually gone away'.
Perhaps BT has adopted the same strategy?
I'm fairly convinced that the problem is linked to graphic images - I've even had the BBC News app on my ipad give me all the text for every item, but no images at all - and a few sites appear as text only in an odd format, as others have illustrated in this thread. I suspect that the sites which won't respond at all are trying to send an image (their header logo?) first, before any text, and blocking the link.
Seeing as we're clutching at straws here, I'll throw in one which is probably pure coincidence: just before these problems started for me, I turned off the "Hotspot" feature that came pre-set on my Home Hub. I can't see any connection with the problem and really don't want to turn it on again to see if things improve, but just wonder if anyone else had turned it off just prior to hitting the problem? As I said... clutching at straws, but I guess something like that might explain why most users don't seem to be affected?!
I think we're all clutching at straws here but the BT DNS unreliabilty issue appears to be well known to those who specialise in knowing about such things.
Try Googling 'BT's DNS servers are rubbish' and see what turns up ... always assuming they are working at the moment, that is.
I have heard that there are some customer's of another well know ISP who are suffering a very similar issue. Sites like BBC/Facebook etc not loading or being very slow to load.
I'm on day 3 now of good web access, since changing the name of my Home Hub (which is a HH2, not a HH4, as I've been with BT for years as I'm out in the sticks with not a lot of other options). Graphics are a little slow to load on Facebook, but they do appear.
Not sure I agree with some other posters that this problem is "intermittent" - it wasn't with me. All was fine during the day (which proves it's not my equipment), then every evening without fail at around 3-4pm the trouble started, and stopped again around 10pm, which is what's been reported by most other posters. Weekends were atrocious whatever the time. Yet my connection speed is alway stable and never slow, so it's not traffic congestion.
I'm not technical at all so have no answers, but it's definitely a problem which will need to be resolved by BT as we all seem to be using different devices, Home Hub versions, versions of windows, parental settings (I don't have kids so they've never been activated) etc, so it clearly isn't a problem caused by their customers. I've had excellent BT connection for 10 years until 4 weeks ago when this issue started, with no change to equipment or software.
I'll report back if my sites stop working again.
having the same intermittent problems with BBC, Facebook, iamazon.co.uk, investorschronicle ...faily random but many of the sites either don't load or are not rendered and have no images and plain text
Speedtest shows I have 8Mb download speed
many other web site work no problem and are def not cached
this has been happening on and off for a few weeks now
on HH4 , wired, wirelses, pc, laptopx 3 (win 7x64on all 3 ), and iPad all showing same issues