BT's scheme to roll out broadband Digital Subscriber Line (DSL) services to more regions only if specific numbers of potential subscribers first register their interest has been roundly criticised - primarily by people living in areas where no trigger levels for the local exchange upgrades were set.

In October BT produced a list of 322 exchanges that it considered "unviable" for upgrade. A month later, however, the company announced a list of 2,300 exchanges that had again been reviewed and had now been given targets. Many of those previously deemed unviable are on this new list.

Within five miles of my house there were four rural exchanges on the unviable list. All of these now have targets and, in one case, the target is considerably less than the number of registrations, meaning it is immediately triggered and should start delivering broadband services in the next few months.

This, on the face of it, is very good news because many more locations will have access to the benefits of broadband services. But not everyone is happy.

Many communities whose exchange was previously classed as unviable got together to find alternative ways to obtain broadband. Consequently, wireless broadband systems are currently being installed in a lot of places, and the people who have put their time and money into these systems now see little chance of getting their money back because BT has suddenly changed its mind.

Of course, all's fair in love and business, but BT's action looks a little peculiar, to say the least.

BT is now saying that it can achieve 100 percent coverage of the country in 2005 through a combination of wired and wireless technologies. Again, this is good news but we should really be looking further ahead.

We're all familiar with Moore's law - that the number of transistors on a chip will double every two years - but it is not generally known that data access rates follow a similar exponential curve.

The introduction of ADSL is a significant leap, providing eight times the throughput of modems and ISDN. However, by the time BT has completed the ADSL rollout, many users will be looking for the next step up.

DSL technology working on copper wires is quite close to its theoretical speed limit and we will not see very much improvement in the next few years.

At some point BT is likely to introduce Very-High-Speed DSL (VDSL), which will give speeds up to about 20Mbit/s but will require a high penetration of fibre-optic cables in the local network. This will probably lead to another rollout driven by demand.

What's after VDSL? Short of wiring up every house in the country with fibre-optic cable there is only one game in town and that is wireless. Wireless puts no real physical limit on the bandwidth that can be achieved, and also provides the possibility of truly mobile broadband services.

Wireless systems are so important for the future that we should be using them now.