If you want internet that actually works, do not ever consider BT Business Broadband.
With previous ISPs I have had ('consumer' services), I've been used to it stopping working occasionally. That's OK. It only happened once every 2 or 3 months, and rebooting the router would tend to fix it straightaway. Besides, I was living out in a rural area, so I would cut them some slack as the exchange probably wasn't very modern, and I was probably approaching the max distance from the exchange at which ADSL works.
BT Business Broadband is a whole different ballgame. I'm now smack in the middle of London, but for the past year or so, on average roughly once a week, it stops working for no apparent reason. Rebooting the router generally does nothing - it'll be down for anything from 10 minute to a few hours, and there's nothing to do except wait.
Today, it's just been down for about three hours, after which it sort of started working. "Sort of", because they intercept every web page I tried to visit and redirected me to this message:
You have been connected to this page due to one of the following reasons. You must now shut down your browser and Internet applications before attempting to reconnect.
1. The BTWholesale access circuit to your Service Provider is currently down. Your service should be resumed soon...
Excuse me? The BT "Wholesale" circuit to my provider? No, you inept bunch of cretins, you ARE my "service" provider, at least given the world's most flexible definition of "service".
Then I noticed something strange. Accessing sites by IP address worked fine. (Last year I went through a period where it would fail to work pretty much every day, and I've bookmarked google by IP, as a means of testing if the problem was DNS or actual connectivity). So I switch my primary DNS server to a non-BT server, and oh look - everything actually works fine!!
What the f***? You're telling me that when your DNS server breaks, you just sit there not working at all for three hours, then displaying the world's most useless and inaccurate error page, instead of just SWITCHING TO A SECOND F***ING DNS SERVER? You're BT for god's sake, surely the biggest networking company in the country, and you've only got one DNS server!? Or what!?
Meh, I don't know; I'm no expert on this. Maybe my diagnosis is completely incorrect. All I do know is that BT Business Broadband is an ABSOLUTE JOKE and on no account should you ever even consider paying for it. The reliability would be piss-poor if this was advertised as a consumer/home service - as it's pitched (and priced) as a business service it simply defies belief. Fortunately, I don't pay for it (my flatmate's employers do), but I know next month when I move flat and have to pay for an ISP, I will be choosing anybody but BT.