Energy prices differ between regions by up to £92 a year and some of the highest costs hit areas with the most unemployment, a study has found.
Merseyside and North Wales are charged the most, with a typical annual bill of £1,373, research by price comparison service energyhelpline.com revealed.
Those in the South East pay £79 less a year, with bills averaging £1,294, while the cheapest area for energy is north Scotland where households typically pay £1,281 a year.
Unemployment in the North West is now second-highest in the UK, with 9.4% of adults out of work, with unemployment in Wales at 9%, according to ONS figures.
West Midlanders face the second-highest bills in the UK at £1,333 a year, followed by central and southern Scotland (£1,329), the rest of the North West (£1,316) and the South West (£1,316).
The cheapest regions in the UK after north Scotland are the East Midlands (£1,291), London, (£1,293) southern England (£1,294) and the South East (£1,294).
Energyhelpline director Mark Todd said: "It's a cruel irony that the areas being landed with the highest bills are the ones where cash is most strapped and where people are struggling to find employment. This postcode lottery places extra strain on squeezed budgets and could throw more people into fuel poverty.
"Our latest quarterly price survey shows that there has been no let-up for those hit with the highest prices.
"It is difficult to explain the reasoning behind these regional price variations other than the fact that regional suppliers charge what they think they can get away with. Often, loyal customers stick to the same regional suppliers rather than switching, meaning profit hotspots arise.
"By switching suppliers, customers are standing up for themselves and showing that they will not tolerate high prices. We expect to see energy price increases later this year, so it will be interesting to see what impact this will have on the postcode lottery across the UK. It is likely that the gulf between energy prices will continue to grow."