Centrica blamed a "challenging environment", singling out the energy price cap and falling natural gas prices, for a £1.1bn annual loss that sunk its share price. Gas prices remain at record lows as the likes of Norway, Qatar, and Russia export large volumes, creating a glut. That contributed to Centrica taking a £1.75bn hit in one-off charges, with a £476m writedown on the value of its oil and gas production assets and a £372m charge on its stake in UK nuclear power plants. “The gas market is very oversupplied right now because of associated gas from shale oil in the US and lower levels of demand in Asia and to trump it all the coronavirus,” said chief executive Iain Conn. The company has been rocked in recent years by a customer exodus and razor-thin margins in the face of intense pressure from smaller suppliers offering cheaper deals. Centrica lost 286,000 accounts last year, but added 28,000 customers in the last three months of the year as it hit back against smaller rivals by introducing more low cost tariffs. However, Centrica said pre-tax losses hit £1.1bn, compared with a £575m profit the year before, after almost all of its gains in the consumer division were offset by losses in the company"s upstream business. Shares fell almost 18pc to 69p, wiping hundreds of millions off its market value. It was Mr Conn"s last set of results as chief executive, after he announced last July that he would step down this year. A search for his replacement was continuing, although the company failed to mention it on Thursday. Centrica said this week that chairman Charles Berry was taking a leave of absence due to an unanticipated medical condition. Scott Wheway will act as interim chairman. Analysts at RBC Capital Markets said progress had been made with growth returning to in the consumer divisions and welcomed a more simplified business model and a renewed focus on efficiencies. However, they added: "Commodity weakness is a concern, a new CEO needs to be appointed and investors will be very disappointed to receive yet another profit warning from a company that has a very poor recent track record on meeting market expectations on financials." In 2015, the group embarked on a turnaround strategy that sought to arrest its decline amid mounting debts, steep losses and heavy pressure from regulators. In a bid to stem losses, Centrica previously said it would cut thousands of jobs and slash spending and aims to reduce costs by £350m this year. The outlook remained bleak as commodity prices meant that cash flow from its upstream oil and nuclear assets could fall by about £200m. Centrica"s exploration and production division - which has long plagued the balance sheet - could be loss-making in 2020, it added. Bids were expected for Spirit Energy, a North Sea oil explorer, by the end of the first quarter. It was reportedly valued at about £1.5bn. Despite previously stating that it would have sold its nuclear assets by the end of this year, Centrica opened up the possibility of retaining them beyond that deadline. "Operational issues at Hunterston B and Dungeness B have impacted the [sale] process, and while we are still pursuing the divestment, we may not be able to dispose of all of our share in a single transaction," the company said. The report suggested a partial nuclear sale remained a possibility in 2020. Centrica has been considering a sale of its entire stake in the £6bn reactor fleet since 2013, but has struggled to find a buyer after revelations about the plants’ rapidly declining health.