SSE has reported a 19.3% drop in full-year pre-tax profits to £593.3m after lower energy prices and increased competition took their toll on the firm.

The company, one of the country’s largest energy suppliers, was hit hardest at its wholesale business, which saw adjusted operating profit drop 6.6% to £442.5m. Profits at its gas production arm fell 94% to £2.2m.

Chief executive Alistair Phillips-Davies said: “The operating environment presented a number of complex issues, including the impact of prevailing commodity prices and intense retail market competition. At the same time, SSE has continued to demonstrate financial discipline and commitment to its long-term strategic framework.”

SSE, which lowered energy prices for its 8.5 million customers in January, said retail operating profit was broadly flat at £455.2m.

On an adjusted basis, pre-tax profit was down 3.3% to £1.5 billion across the company.

Mr Phillips-Davies added: “The fact that some of the mist is beginning to clear around the legislative, political and regulatory environment means there are grounds for some cautious optimism for the next couple of years.”

SSE lost 370,000 customers over the year and was slammed by consumer group energyhelpline.

Mark Todd, co-founder of the energy price comparison site, said: “SSE has lost customers yet is making the same amount of money as last year - £1.5bn.

“This is not a magic trick, it’s a cunning trick. SSE have simply passed on price cuts as slowly as possible and have made more money per customer.

“This year they were joint slowest of the Big Six to pass on a price cut. Last year they were the slowest.

“SSE could be cutting prices quicker and deeper. We call on them to give an immediate 5% price cut to their loyal customers today. They deserve it.”