Utility firms have been accused of greed after turning down an offer to become the preferred supplier to more than half-a-million people.
MP Tom Clarke said the campaign in Lanarkshire would go on
Seven power companies were invited by Labour MPs and two local authorities to offer a cheaper rate of gas and electricity in Lanarkshire.
Energy suppliers declined the offer and said it would be discriminatory towards other areas of the UK.
Lanarkshire MP Tom Clarke said the energy firms were being unreasonable.
The area's Labour MPs spent six months trying to create a special discounted area of more than 300,000 homes.
In return, the preferred supplier would stand to gain customers and have the backing of two councils and MPs, among them Home Secretary John Reid.
Each power company declined the offer. One described it as an odd proposal.
They said the competitive market allowed consumers to choose supplier and pointed out EU rules prevent differential pricing that would discriminate against households outside Lanarkshire.
Tom Clarke, MP for Coatbridge, Chryston and Bellshill, said he had seldom heard a weaker argument.
"The companies are being pretty greedy and pretty unfair," he said.
"If the companies had been reasonable, they could have passed on the benefits they have enjoyed over quite a lengthy period in the reduction of wholesale prices to elderly people, low income families and vulnerable people.
"We wanted to see the reduction passed on to the consumer in terms of lower prices, it is a very simple thing to do."
Mr Clarke said the campaign would go on.