I had the same problems as IanR's comments below.
JUNE
Could only get a measly 0.5mb connection for ages and the phone line was all crackly.
I called them to get the problem fixed and was threatened that I would have to pay a large sum of money if the fault was caused by me.
They then arranged engineer dates where nobody showed up. Not good when you take a day off to meet them.
Was promised that they would call me the next day to check if the problem had been resolved. No phone call/s.

NOVEMBER
Passed to a emergency department where I was treated like an idiot again with the threat of a large penalty fine.
The not so caring lady then proceeded to be as rude as possible.
Got promised a compensation payment which they never followed through with.
They also would not pay from the time I first called them. Only from the time I was passed to the emergency department which was decided by them. Oh yeah, and only if they do not fix it within 14 days of this current call.
Engineer finally comes out and makes the line worse.
More phone calls and broken promises.
Another two engineers come round and do their best to sort it out.
Finally I have a 2mb average connection which is a big difference from the 14mb my line is supposed to be able to handle. I am aware of the variables that affect speed but that is just not good enough.
My iphone 3g wireless tethered connection gives me 3mb.

December
Just called them to get my MAC code to change provider and have been informed that I can get Infinity for a couple of pounds cheaper than Total Broadband with reliable speeds of up to 15mb guaranteed or they will not supply it to me. WHY DID NOBODY SAY THIS BEFORE!
They also finally decided to compensate me for the poor service £19.72.
They now want £120 to cancel the rest of my contract.
They are trying to get me to sign into a Infinity package with a new 18 month contract which I would have to pay a bigger cancellation fee when not happy with the service.
Avoid BT like the plague if you are looking for a service provider.
Please use a speed checker if you are a current BT customer and se if you are getting what you have paid for.