Over one third of a million Scottish households will miss out on Step Change

Click on these buttons to see the estimated percentage of stillslow households ...

Proportion of households with lines too long for superfast. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% AB DD DG EH FK G HS IV KA KA KW KW KY ML PA PH TD ZE ZE

The 'Step Change' programme uses FTTC technology. FTTC stands for fibre to the cabinet, or, since FTTC uses existing copper lines to connect from the cabinet to the home, fibre to the copper. The speed of the connection is limited by the length of this copper connection.

Some homes are too far from the cabinet to enjoy superfast speeds. Taking Scotland as a whole, the proportion of stillslow homes is small, but in some areas it is significant. Our calculations are based on a 1.2 km theoretical limit for superfast speeds (> 30 Mb/s). Since most connections are less than ideal, the practical limit will usually be shorter.

In some areas, there are no cabinets; homes are served by 'exchange only' lines. If the line to the exchange is short enough, it can be used to deliver superfast broadband. Again, we apply a 1.2 km limit for superfast speeds.

Depth of colour indicates the estimated proportion of households that have copper lines too long for superfast. This ranges from a high of 61% in the Western Isles (HS), to a low of 8% in Edinburgh (EH). Even if every exchange and every existing cabinet were upgraded with FTTC (fibre to the copper), these households would not be able to access speeds of 30 Mb/s without the construction of new cabinets.

Click on any Postcode Area on the map, or select a Postcode Sector using the Postcode Sector button, to show a detailed view nearby Postcode Districts.

Again, each district is coloured to show the estimated percentage of homes that will still be slow, left without superfast, until more cabinets are built. Darker red means more still-slow lines. The maps show Postcode Districts (e.g. AB53 : 47%), but there is often wide variation between the sectors within a district (e.g. AB53 4 : 23%; AB53 5 : 77%), so it is worth looking at the details by Postcode Sector. However, the figures for small Postcode Sectors could be significantly affected by small errors in the available data. (around 20% include less than 1,000 households, most have more than 2,600).

These estimates are based on line-length data where it is available, combined with census data for the number of households in each postcode. Where a postcode is served by more than one cabinet, we split the households evenly between the cabinets.

Where we have no cabinet data we have assumed there are exchange-only lines. We have estimated the distribution of line lengths for each of these postcodes, by calculating the distribution of line lengths (to the exchange) for postcodes in the same urban-rural geography at a similar distance from the exchange. We have no data on any planned new cabinets. We will be happy to modify this site, to include data on new cabinets and actual lengths of exchange-only lines, if this is made available.

For more discussion, see our note What will the current fibre roll-out achieve?

Michael Fourman, Peter Buneman, School of Informatics, The University of Edinburgh
Last modified: Wed Feb 26 23:12:12 GMT 2014