This chapter focuses on those relating to oil and gas. In the Base Case, the total UK crude oil recoverable reserves are assumed to be 150,000 PJ. The High oil reserves estimate adopted for the sensitivity analysis is double the Base Case reserve assumption, that is, 300,000 PJ. International oil and gas prices have been assumed to rise by 3 per cent per year up to the end of the century, by which time they would be double their 1977 levels, and to remain constant after the year 2000. The minimum cost energy policy is thus quite robust with respect to the levels of UK oil and gas reserves but more sensitive with respect to rate of increase of world prices of these fuels. The Base Case assumes that world oil and gas prices rise at 3 per cent per annum up to the turn of the century, after which time they remain constant.