In total, the company said that it made more than 1 million home visits to install the meters.

Following a two-year installation programme, ScottishPower claims that it has become the first operator to replace all of the meters in their network area. Apart from fitting over 300,000 new meters, the company has also carried out information campaigns to ensure that all customers were aware of the upgrades.

The company said that the upgraded technology will benefit customers in a number of ways. Data can be updated remotely, meaning that physical access to the meter is no longer required beyond standard safety checks. A meter reading is also automatically recorded every time the key is re-inserted after adding credit, which reduces the possibility of inaccurate bills.

In addition, Key Meters are programmed to ensure continued electricity supplies if credit runs out during the hours when it is difficult to purchase top-ups.

Neil Clitheroe, customer services director of ScottishPower, said: “Our engineers have worked hard to deliver this major investment in very good time. During the peak of the replacement programme, we were upgrading 3,000 meters every week.

“The new meters are more user friendly than their predecessors, and customers will see immediate benefits. Greater accuracy in recording readings and the ability to update information remotely will significantly reduce the possibility of billing inaccuracies. It will also reduce the possibility of debt being accumulated.”

ScottishPower said that it used a phased approach to introduce the new meters, carrying out the upgrades one area at a time. The first region to be fully upgraded was Dumfries & Galloway in January 2009, with the final areas of Glasgow and Caernarfon completed at the end of August.