The packs, which were due to come into force next week to accompany every property sale, have been postponed until August 1 and at first will be introduced only for four-bedroom or larger houses - less than 20% of the market.
Ms Kelly admitted to the Commons that not enough assessors were yet in place to carry out checks for energy performance certificates, which are a key component of the packs and are intended to improve the environmental efficiency of UK homes.
She could not say when the packs would be introduced for smaller homes and the government also admitted it did not possess a legally watertight definition of a four-bedroom house - making it likely that a rash of "three-bedroom houses with study" will suddenly flood the market as a way of avoiding costly Hips.
The packs were first promised by Labour in 1996 in an effort to stop so many house sales falling through. More than one million homes are bought and sold every year, but a quarter of deals collapse. The information packs, already watered down last year, had been due to become mandatory next week but Ms Kelly and the housing minister, Yvette Cooper, sounded the retreat after a successful private application for judicial review of energy performance certificates by the Royal Institution of Chartered Surveyors.
A judge agreed that the certificates should not yet be included within the packs. The RICS agreed to stay its legal challenge after talks with ministers ended with the government agreeing to hold a fresh 12 week consultation on the certificates.
Only 520 energy assessors have so far been accredited, a quarter of those needed by June 1. Ministers blamed Conservative critics for creating uncertainty over Hips - thus making would-be assessors reluctant to pay for the £300 accreditation course.
Michael Gove, shadow housing minister, said the stability of the housing market and the battle against climate change had been damaged by government "arrogance and incompetence".
Guardian Unlimited © Guardian News and Media Limited 2007
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