The speed issue could be down to the following reasons:
(1) your ISP has installed and using 33.3k modems -
freeserve and NTL do this (most likley)(2) the Cabling in
your street is old and crap - or this could be the
exchange, older exchanges (10 years or more) were not
designed to carry internet traffic and the copper could
be loosing connectivity or the speed has been reduced to
allow better connectivity (loss of connection) (3) Your
cabling could be fibre optic, sound mad but BT claim that
they cann't connect fibre and copper together at fast
speeds - it means spending money and they dont wanna. (4)
Go to broadband because this problem is not due to you.
hope this helps
John
