Electricity Alliance East, a National Grid-led partnership with Balfour Beatty, has built tall electricity towers in North East England as part of the Tees Crossing overhead line project in the UK.
The towers stand 145m tall and will support 400kV electricity line across the River Tees near Middlesbrough.
Electricity Alliance carried out the tower construction work and upgraded and renewed the electricity transmission network in England and Wales.
Electricity Alliance East head Alan MacKenzie said the project had numerous challenges.
"The height of these towers has also made the job technically very challenging. The towers required very deep foundations due to both their weight and the ground conditions," MacKenzie added.
"Even topping the towers out has proven difficult; with the weather conditions having a much greater impact on work than they normally would, and wind speeds in particular requiring careful monitoring to ensure safety.
"Topping out some of the UK’s tallest electricity towers is a great opportunity to showcase the work that goes into providing the electricity that we all rely on every day."
The new towers are only a section of the Tees Crossing project, which involves the construction of 14 new towers in total and the upgrade of another 32 towers along a 13km route.
The project is due for completion in November 2013.