TWO leading energy firms have reported a significant drop in profits due to a slump in consumer fuel use.

British Gas, the UK's biggest gas supplier and which trades as Scottish Gas north of the Border, saw a 30% decrease in profits to £522 million last year, while ScottishPower yesterday reported a 40% drop to £273m.

Energy giant Centrica, owner of British Gas, which lost 97,000 customers in 2011, said the unseasonably warm weather in spring and autumn led to a 21% drop in average household gas consumption and a 4% fall in electricity use.

Iberdrola, the Spanish firm behind ScottishPower, attributed the downturn to tighter margins and a decrease in demand for energy.

However, Consumer Focus Scotland argued that, despite the drops, the companies still secured "healthy profits" as customers continued to pay expensive fuel bills.

Trisha McAuley, deputy director at the consumer group, said: "It is not surprising British Gas's overall profits are down, with customer energy-use falling by 21% for gas and 4% for electricity. What both firms' results show, however, is that the energy industry is close to recession-proof. Healthy profits are still being made despite a big dip in consumption over our mild winter this year.

"The results of British Gas, ScottishPower, and predictions for SSE, all show fairly steady profits can be made in the energy business in all circumstances. That is the opposite experience of their customers in Scotland who have seen bills soaring when wholesale prices have risen and only small cuts when costs have fallen."

She added: "What we need to see is the regulator ensuring customer information from energy suppliers is fully transparent, comparable, and includes profit and trading information from across the whole of the business."

The slide in profits for British Gas comes despite the energy supplier hiking gas and electricity bills by an average of 18% and 16% respectively in August.

It has since announced a 5% cut in electricity prices in January.