AROUND 100,000 people have pulled the plug on ScottishPower, records reveal.

The Glasgow-based firm has suffered a six-figure drop in residential customers.

The number of accounts it serves fell from five million in the first quarter of this year to 4.9m in the second.

The figures were released yesterday as parent company Iberdrola, a Spanish multi-national, issued a results update which also revealed that earnings in ScottishPower’s home supply arm had shot up by 306% in the six months to the end of June.

The boost, which took takings to £165.8m, was described as a “recovery” on poor performance in 2017.

Householders across the UK were forced to use more power in their homes, with a focus on heating, as the “Beast from the East” weather front brought record snows in late February.

The freezing spell lasted into early March, which helped push average customer energy use up by 4% year-on-year over the entire reported period.

Reflecting on the results, ScottishPower head Keith Anderson said he is braced for continued “challenging” conditions in the rest of the year as regulatory changes approach.

These include a price cap approved by the UK parliament last week.

It aims to reduce charges for around five million households.

ScottishPower’s updated customer numbers follow news by the “Big Six” company that it will raise gas and electricity prices for around one third of its customer base – almost one million users.

The 5.5% hike came into effect from June 1 and takes standard dual-fuel bills for those paying by direct debit to £1211 a year, amounting to an increase of £63.

The change is attributed to a jump in wholesale energy costs, as well as costs associated with upgrading metres and delivering energy from low-carbon sources.

The firm has been investing in wind power, having completed a £650m project to build eight wind farms in Scotland.

Over the first six months of 2018, ScottishPower also began construction on an offshore wind farm in East Anglia, a project known as East Anglia ONE.

Anderson said: “All of our business areas are performing in line with expectations.

“Our investment in onshore wind last year has seen an increase in electricity generated, and excellent progress has been made on delivering the £2.5 billion East Anglia ONE project. We expect first generation of electricity next year. Networks also continues to see major investment.

“We are delivering a smarter and more robust grid system to support renewable energy connections, as well as planning for the anticipated increased uptake of electric vehicles in the years ahead.

“Generation and supply has improved on the poor results in 2017, moving towards a more typical year.

“We expect further details on the proposed price cap in the second half of the year, and expect the market to remain challenging.”

Iberdrola’s net ordinary profit rose by around one third to reach €1.367bn in the first half of 2018, something attributed to “the positive performance of international business, the growing return from the €20bn invested over the past five years, improved efficiency and the normalization of the operating conditions in its core markets”.