Interim household growth figures, due to be updated as early as next year, claim that the number of households will grow 26 per cent faster than was projected in previous set of estimates, made five years ago.

But the Campaign to Protect Rural England (CPRE) is urging government ministers not to sacrifice the environment in a rush of house building to meet the new growth figures.

The Office of the Deputy Prime Minister is suggesting that the annual increase now stands at 189,000 households a year, equivalent to growth of 3.8 million over the next two decades.

But, says the CPRE, the ODPM is hedging its bets in two critical ways. First, it points out that the figures are soon to be revised in the light of the 2001 Census and 2003-based population projections.

Second, it points out that the interim projections assume an unconstrained supply of new housing and average household size continuing to fall.

The Campaign to Protect Rural England's head of policy Neil Sinden said "If the Government reacts to these projections by proposing big increases in the output of new homes, along the lines of the Barker Review, it could lead to an environmental disaster - and quite possibly a social one too."

"These latest projections are estimates based on previous trends, not a forecast of what is actually needed or desirable. You can't look at this as simply a matter of raising supply to meet demand, because while many people can afford a couple of homes many more can't afford even one."

"Instead of concentrating on demand, we should be thinking about people's needs - especially the needs of the housing have-nots."

Major increases in house building also have severe environmental consequences, points out Sinden. It's not just a matter of building over the countryside. New housing, especially on greenfields, means extra traffic, more burning of fossil fuels and greenhouse gas emissions, more water consumption, quarrying and all sorts of associated infrastructure.

The CPRE is urging the government not to revert to 'predict and provide', but to think about how to manage the demand for housing. We need more affordable homes, and we need to press on with regenerating our towns and cities, making use of the huge areas of derelict brownfield land for new housing and raising housing densities from wastefully low levels.