Most experts do not agree with David Cameron's claim that fracking will cut UK energy bills, the advertising watchdog has concluded.

The Advertising Standards Agency (ASA) has now overturned the decision it took last year to ban a Greenpeace anti-fracking advert, which stated that "experts agree - it won't cut our energy bills".

At the time, the ASA cited the fact David Cameron had said fracking would cut energy bills as evidence there was "a significant division of informed opinion on the issue" and so ruled that Greenpeace's advert was "misleading".

But after an appeal by Greenpeace and an independent review, the ASA has reversed its original decision, concluding it was "substantially flawed".

An ASA spokesman said that, this time, it had decided to "focus only on the opinion of experts in this field and not those of others such as the previous Prime Minister".

After reviewing the expert evidence again, the ASA said in a new judgment: "The general consensus among most appeared to be that a meaningful reduction in UK domestic energy bills was highly unlikely and/or was limited to a small number of potential scenarios."