This is an example result from using BT's line checker:

Line check result

Key:

  1. If you are not on a direct line to the exchange the number of the street cabinet you are connected through will be shown here.
  2. The "Range" lines will not be present if FTTC is not currently available to you. If it is, you can choose between two speed options (with a cost difference, of course). "Impacted" speeds are those expected if there are certain problems with the line.
  3. For a "traditional" ADSL broadband connection, this is the expected download speed range.