In a joint review with the watchdog Consumer Focus, Ofgem found suppliers were disconnecting vulnerable customers who had not paid their bills last winter, despite this being against their licence conditions. Consumer Focus had dealt with "dozens" of distressed customers who found their supply had been cut off, which it described as a "devastating" blow during the winter.
Vulnerable customers are those on low incomes with young children, and people dependent on medical equipment run by electricity, such as electric wheelchairs and kidney dialysis machines.
Under their licence conditions, suppliers should not disconnect them during the winter months when temperatures plunge.
In a package of reforms announced by Ofgem recently, suppliers agreed to re-connect a disconnected customer who turned out to be vulnerable within 24 hours.
Suppliers also committed to contact customers who had been disconnected to check again that they were not vulnerable. They also committed to improvements in their treatment of the mentally ill.
Sarah Harrison, an Ofgem spokeswoman, said: "This thorough review shows that, while suppliers' procedures in this area are generally sound, improvements can be made. Ofgem is proposing changes to the existing rules to ensure that the regulatory framework is fit for purpose and is working with suppliers and the Energy Retail Association to ensure the elderly and other potentially vulnerable customers are better protected ahead of the forthcoming winter."
Audrey Gallacher, an energy expert at Consumer Focus, said: "In spite of a licence condition and an industry-wide safety net to prevent vulnerable consumers from being disconnected, dozens of vulnerable households needed urgent help from our Extra Help Unit to get their supply back on last winter."