§ Mr. Simpson
To ask the Secretary of State for the Environment if he will estimate the percentage of extra fuel which is required to heat identical houses in(a) Nottingham and (b) Derby, taking Bristol as the base. 
§ Mr. Robert B. Jones
The percentage of extra fuel required to heat a typical semi-detached house with gas central heating is estimated to be as follows for each of the specified locations:
- (a) Nottingham +17 per cent. and
- (b) Derby +17 per cent.
These figures have been calculated using the Building Research Establishment domestic energy model and taking Bristol as the base case.