British Gas owner Centrica has initiated a £182m lawsuit against IT supplier Accenture, which it hired to implement a customer billing system in 2001.

When the system was rolled out in 2006-2007, Centrica's suffered a huge rise in complaints to Energywatch from its customers, which have now fallen by 85 per cent.

In addition to the initial £300m investment in the system, British Gas was forced to make ongoing investments, including recruitment costs to address the system failures.

In a statement, Centrica said: "An independent analysis of the billing system has concluded that Accenture was responsible for fundamental errors in the design and implementation of the system."

"Unfortunately British Gas has been left with no option but to pursue legal redress against Accenture to compensate for its losses."