The joint PHE-BGS digital radon potential dataset provides the current definitive map of radon Affected Areas in England and Wales. It will also allow an estimate to be made of the probability that an individual property in England and Wales is at or above the Action Level for radon. This information also provides an answer to one of the standard legal enquiries on house purchase in England and Wales, known as CON29 standard Enquiry of Local Authority; 3.13 Radon Gas: Location of the Property in a Radon Affected Area. The radon potential dataset will also provide information on the level of protection required for new buildings under as described in the latest Building Research Establishment guidance on radon protective measures for new buildings (BR 211 2007). This radon potential hazard information for England and Wales is based on Public Health England (PHE) indoor radon measurements and BGS digital geology information. This product was derived from DigMap50 V3.14 and PHE in-house radon measurement data. The indoor radon data is used with the agreement of the PHE. Confidentiality of measurement locations is maintained through data management practices. Access to the data is restricted. This dataset has been superseded by PHE-BGS Joint Radon Potential Dataset For Great Britain. Radon is a natural radioactive gas, which enters buildings from the ground. Exposure to high concentrations increases the risk of lung cancer. The Health Protection Agency recommends that radon levels should be reduced in homes where the annual average is at or above 200 becquerels per cubic metre (200 Bq m-3). This is termed the Action Level. The Health Protection Agency defines radon Affected Areas as those with 1% chance or more of a house having a radon concentration at or above the Action Level of 200 Bq m-3. The dataset was originally developed by BGS with the Health Protection Agency (HPA) which is now part of Public Health England.