This is the problem I have with this issue when people start talking about things like energy prices, this is perhaps the most basic and flawed way of interpreting the data. I'm not saying the energy companies AREN'T ripping off consumers, but lets at least look at the real facts.
First off, the figures are not adjusted for inflation. £49 in 1999 is closer to £68 today. Not a monumental difference, but a difference none the less and should be remembered.
Next, here are a couple charts on the spot prices for oil and natural gas (in USD) adjusted for inflation. Notice that on the charts, 1999 is a historical low in natural gas and a near 40 year low for oil.
Also lets remember that in the last decade, Green issues have come to the forefront of politics in the form of extra regulation. I'm sure this has resulted in some increase in price, for example I remember watching a show on the BBC not long ago which mentioned how one of Britains biggest coal power plants had shifted to 10% biomass.
Again I'm not saying there isn't something dodgy going on, but let's not go all Daily Mail and start throwing our toys out of the pram before you actually look at the facts behind things like these price rises.