Speedtest.net is unreliable now....... or so i was told by the virgin engineer.
Virgin Engineers use this for actual Speed Testing for Virgin Networks :http://126.96.36.199/speedtest/login.php
User ID is : virgin
Password is : wolverhampton
On next page Select 'DUDLEY'
Change Size drop-down to '100MB'
Select ' Start Test'
Note: this is for 50Mb so may not be accurate for others speeds but bound to be more accurate than anything else on the net.
Also try the File Downloads at the bottom of the page and calculate speeds yourself !!
*** NOTE : Make sure all peer-to-peer programs and anything else that hogs your internet connection are also turned off ***