The Department is unable to provide historical data covering the last 30-year period. Ofgem the industry regulator has provided comprehensive data covering the periods 2005-06, 2006-07 and 2007-08 for both transmission and distribution networks across England, Wales and Scotland. These details are contained in the following table.
Total added Overhead Underground Percentage underground 2005-06 10,368 3,162 7,206 70 2006-07 7,685 1,941 5,744 75 2007-08 8,582 2,225 6,357 74
A large amount of new power lines are low voltage distribution lines in urbanised areas.