It's a well known fact that BT's existing telecoms infrastructure is largely based off copper wire, which carries most of the UK's voice, broadband ADSL (8Mbps) and ADSL2+ (24Mbps) services. Unfortunately copper can only carry so much information and is negatively impacted by longer distances, which is partly why BT recently announced its £1.5bn plan to rollout a new 'up to' 100Mbps fibre optic (FTTP) network (original news).

However, under BT's plans, many existing premises will instead be given access to Fibre to the Cabinet (FTTC) technology. FTTC is seen as a good way of saving money because it only requires that part of the local loop be replaced with fibre, while the bit going from your local cabinet to the home remains copper. Naturally this method offers less speed, although at 40 to 60Mbps it's nothing to sniff about.

FTTC also requires some form of DSL (e.g. VDSL/VDSL2) broadband technology to fill the 'last mile' into people’s homes. It's for this reason that Ofcom has today published new research into the theoretical limits of copper in the last mile (here), which essentially examines precisely what is capable via existing infrastructure:


Naturally VDSL, as a 'last mile' solution, is not immune to the problems of line length and Ofcom's research reveals some fascinating information. Unfortunately there are many different predictions and test methods, making it difficult to generalise. However, it does appear as though FTTC/VDSL would allow even those at the extreme end of their exchanges reach to receive speeds of 'up to' 10Mbps, which is a far cry from today’s 512Kbps (0.5Mbps).

Most consumers could of course expect far faster speeds, with something closer to 30Mbps becoming the probable norm.