 SOaRING ENERGY costs have left a quarter of households struggling to pay their bills. The average cost of gas and electricity is now ?1,293 a year and getting closer to a ?1,500 a year affordability ceiling.  Research from uSwitch suggests that if that level is reached, three-quarters of households will start to ration energy, three-fifths will go without adequate heating and more than a third of homes will be forced to turn their heating off entirely.  There are now no energy deals costing less than ?1,000. The last - a dual fuel ?990 deal - was pulled by Scottish Power earlier this week. The cheapest deal, reckons Energyhelpline.com, is now EDF's Energy Discount Plan v5, which costs ?1,024 a year.  If bills reach ?1,500, 26 per cent of people say they would be forced to borrow to be able to afford to pay energy costs. While that sounds like a situation you'd expect to find in a third world country, the notion of fuel poverty - when energy costs account for a tenth of more of your income - is fast becoming a reality for millions.  "We are now just ?207 or 14 per cent away from hitting an affordability ceiling after which consumers will start rationing their usage as though they are living in the third world," warns ann Robinson, director of consumer policy at uSwitch.  Richard Lloyd, executive director at Which?, says: "The overwhelming majority of people tell us the price of gas and electricity is their biggest financial worry. The rising cost of living has already forced almost half of us to cut back on essentials, and this was before some of the recent energy price hikes had even taken effect."  The latest figures from the Department of Energy and Climate Change estimate that 5.5m UK households are already in fuel poverty. By comparison, uSwitch research puts the figure at 6.3m households, or 24 per cent of the population.  "People should not be in a position where they are forced to choose between whether they heat or eat, espec 