An eco-friendly pensioner who made her home more energy efficient with Government grants is being fined each week by her electricity firm because she has cut her bills too much.

Margaret Pracy, of Pankhurst Avenue, Brighton, took advantage of the Warm Front scheme to lay insulation in her loft.

She also replaced all her light bulbs with the energy efficient variety, made sure lights were turned off if she was not in the room and put a brick in the toilet cistern to conserve water.

But the 61-year-old has now received a letter from British Gas saying all customers who use less than £9 a week of electricity on the firm's prepay scheme will be charged an extra 54p a week.

She claims she is being punished for watching her pennies and using a prepaid key.

She said: "I don't know why we should pay that little bit more for the same electricity.

"I have had new insulation in the loft and put in energy saving light bulbs, so in effect I am being fined 54p a week for being thrifty.

"I am just unable to save up for bills so I prepay."

She added that many pensioners who lived on their own and were careful with their money were likely to be suffering the same fate.

Green councillor Bill Randall said the system was "complete madness".

"It makes a mockery of insulation programmes,", he said.

Coun Randall urged Ed Miliband, Secretary of State for Climate Change and Energy, to get tough with energy suppliers who overcharge the poorest customers and penalise pensioners for saving energy.

A British Gas spokesman apologised for any distress caused.