From 1 June 2007, most homeowners in England and Wales will have to prepare a Home Information Pack before putting their home up for sale.

The Home Information Pack will bring together key information needed by buyers and sellers at the very start of the home-buying process.

When marketing begins, the Home Information Pack must contain at least the following:

An Index of contents

An Energy Performance Certificate

A sale statement

Evidence of title (for registered properties).
The following documents are also compulsory, but can be added to the Home Information Packlater if there are delays in obtaining them:

Evidence of title (for unregistered properties)

Searches

Leasehold/commonhold documents where appropriate.
The Home Information Packwill also ensure that important information about improving the energy efficiency of homes is made available every time a property is sold.

Where any items are missing, the Home Information Pack Index should explain why. Where evidence of title, searches and leasehold/commonhold documents are missing, the seller must provide evidence that an agreement has been made to provide the documents as soon as practicable and within 28 days, except in exceptional circumstances. If this takes longer than 28 days, marketers will be expected to demonstrate that they have made all reasonable efforts and enquiries to obtain them.

An Energy Performance Certificate shows the official energy efficiency rating of a property. If you're not planning to sell your home, you don't need to do anything.

The certificate provides you with a rating for the building, showing its energy efficiency and its environmental impact on a scale from A-G (where A is the most efficient and G the least efficient), in graphical format. It also contains recommended ways to improve the building's energy performance.

By 2009, all buildings in the UK that are constructed, sold or rented out will have to have an Energy Performance Certificate, in accordance with the European Energy Performance of Buildings Directive.

Predicted and interim energy assessments
Predicted energy assessments are for homes that are not yet built. When a home is designed, a predicted energy rating based on the design is produced. This must achieve, as a minimum, the target energy rating laid down for the home as specified by the energy efficiency requirements of building regulations.

Interim energy assessments are for new homes built in accordance with the energy efficiency requirements of the building regulations that came into force in April 2006. For these homes, until 1 October 2007, only the energy-efficiency and environmental-impact graphs will be required, and not the full Energy Performance Certificate.
source: http://www.homeinformationpacks.gov.uk