Just done a bit of googling. It seems that the Speedtouch is an ADSL modem, so, therefore, you are connecting through a BT phone line, and not the NTL network. Am I correct?
If so, the easiest option would be to get an ADSL router , such as the
Linksys WAG54G. Note, if that link doesn't work, just go to
http://www.linksys.com and search for wag54g