UNDERLYING profits in Scottish Power’s generation and supply business fell by 76 per cent in the first half of this year, with the closure of the company’s Longannet Power Station and the defection of 100,000 customers having an impact.

Earnings before interest, tax, depreciation and amortisation (EBITDA) at the arm fell from £205.9 million in the first half of 2016 to £48.8m after domestic power sales fell by seven per cent and gas sales by eight per cent.

Customer account numbers, which stood at 5.4 million in the first half of 2016, fell to 5.3 million.

Earlier this year Scottish Power hiked its standard dual fuel tariff by 7.8 per cent in a move that would have impacted on around a million of its customers.

Chief corporate officer Keith Anderson said the firm had lost customers due to “fierce competition”, which he said would continue “for the foreseeable future”.

“Even with this backdrop our customer numbers are stable,” he added.

The firm also said that milder weather at the beginning of the year had had an impact on the numbers, while the closure of Longannet in Fife had resulted in UK thermal production falling by 2,342 gigawatt hours (GWh) to 3,581.

This was partially offset by a 48 per cent rise in onshore wind production to 1,701 GWh.

Underlying profit in Scottish Power’s renewables business was up from £116.6m to £153.7m in the first half, a rise of 32 per cent.