93% of telephone lines may manage 2Mbps line speed
2006 has seen an explosion in people connecting to an ADSL line that is running rate adaptive ADSL (RADSL), which is marketed by BT Wholesale as Max, and is also used by the majority of unbundling providers. Some LLU providers do go further and use the faster standard called ADSL2+.
What is crucial with any rate adaptive service no matter which standard is the amount of metallic cable between you and the exchange, followed by its condition and the layout/condition of the telephone extension wiring in your own property. To give people an idea of what speeds their individual line may manage there are checkers like www.btwholesale.com/getbroadband. While the checkers are not always correct, it can help to give some idea of what to expect. Some checkers allow you to use the postcode, this is a lot less accurate than using the telephone number.
Looking at the UK telephone network as a whole, the BT Group website gives some estimates for the percentage of lines that will manage various speeds using ADSL. We have used the ADSL speeds to also give an estimate of the ADSL2+ speeds using the graph located on the Unofficial Be Users Forum.
The advantages of ADSL2+ do tail off very rapidly as line length/attenuation increases, but ADSL2 the standard which ADSL2+ is based on does offer some small improvements for longer lines. It is worth remembering that ADSL2 and ADSL2+ are both based around the ADSL standard, so worst case scenario you should get the same speeds from ADSL2+ as you do from a rate adaptive ADSL service now.