The big six energy suppliers have agreed to stop cold calling customers and respect residential zones that have opted out of receiving such calls.
The development follows a successful campaign by the Trading Standards Institute and Consumer Focus, which argues that energy suppliers need to respect the wishes of consumers who place stickers or notes in their windows expressing their wish to be left alone by salesmen.
British Gas, EDF, E.ON, npower, Scottish and Southern Energy and Scottish Power said they are now committed to respecting consumers' wishes with regards to cold calling.
Clare Corbett, campaigns manager at Which?, said: "This is good news for consumers who have made it clear they don't want to be badgered on their own doorstep. However, energy suppliers shouldn't need to be told that no means no."
In 2008, industry regulator Ofgem found that just under half of consumers who went ahead to switch energy suppliers as a result of a direct sale ended up on a worse deal.
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