I'm just wondering if this is working for any one? http://speedtester.bt.com/
I'm keep getting this error /: "The Performance Tester is currently unable to run a speed test for your broadband connection. Please try again shortly, however if this problem persists, raise the issue with your service provider."
But, both times when I've done the test been raining and thundering. But, other speedtest are working so can't see it being that.
I had a similar problem just like this, when i joined BT i asked to keep my old phone number from Virginmedia but when i ordered my BT pacakge they didnt keep my number, BT provided me with one of their number and later i finally chnaged it back to my old number from virgin.. if this is your case try to use the first number which bt provided you... now this may not be the solution to your problem but there will be a couple of people on this forum which may be encountering this error for the BT speedtester.
sorry if i couldnt be any help.