Environmental charity National Energy Foundation has sold its 56 per cent stake in its trading arm, National Energy Services, to international DIY retailer Kingfisher, whose brands include B&Q.

Ian Byrne, company secretary at National Energy Foundation (NEF), declined to confirm the sale price or give any reason for the sale of National Energy Services, which provides training and qualifications to energy assessors as well as accreditation schemes for energy assessors and home inspectors.

NEF’s most recent accounts, for the year ended March 2010, show it had income of £7.2m, while National Energy Services (NES) had a turnover of £5.9m in the same period, down from £7.5m in the previous year.

The trading arm made a pre-tax profit of just over £9,000 in the year, down from £356,000 in the year before.

The remaining 44 per cent of shares in the company are held by private individuals. Most of these are owned by the company's vice chairman Peter Chapman and managing director Brian Scannell.

NES's latest accounts state: "Activities have switched from the provision of training and assessment to the provision of accreditation and quality assurance services.  This has resulted in a decline in training and assessment income and a relative increase in accreditation scheme income.  Company performance is now sensitive to the performance of the UK property market which has been notably flat in recent months."