The Energy Saving Trust, the government-funded body that is working to reduce the UK's contribution to climate change, has picked Mustoes and Tullo Marshall Warren to handle its communications.
Mustoes' appointment follows a four-way pitch against Euro RSCG London, DFGW and the incumbent, Rainey Kelly Campbell Roalfe/Y&R, which has held the account for the past five years.
Meanwhile, Tullo Marshall Warren pitched against Draft and Rapier.
A new campaign from the EST will continue to educate the public about using less energy in their homes. It will also aim to reduce fuel consumption on roads and to market energy-saving technologies.
The new ads will build on a recent TV campaign by RKCR/Y&R, which featured people who were sceptical about how they could affect climate change simply by turning off lights or their TV. A previous campaign used the idea of electrical appliances behaving badly - swearing at guests or looking up women's skirts - to represent their energy inefficiency.
The new EST drive is set to run alongside a campaign by the Department for the Environment, Food and Rural Affairs, which will focus on changing consumers' attitudes to energy saving. While the EST's activity will centre on above-the-line advertising, Defra will focus on local activities, such as roadshows.
Janet Morris, the director of marketing at the EST, said: "We are now at a turning point. We are moving to the next level of promoting energy efficiency, with a stronger proposition which provides consumers with information and advice to bring sustainable, energy- efficient living to everyone's daily lives."
The EST will play a key role in the Government's pledge to reduce energy emissions in the UK. As part of the Kyoto Agreement, the UK has pledged to reduce its greenhouse gas emissions by 20 per cent by 2010.