ENERGY firms face an Ofgem investigation over a “concerning” rise in the number of struggling households being forced onto prepayment meters. 

The regulator said yesterday that it would also consider taking legal action if firms are found not to have taken due care when moving customers onto the more costly meters. 

Customers who fail to keep the devices topped up with money have their electricity and gas cut off.

In recent months, hundreds of thousands of households have been switched onto prepayment metres, often unwillingly, after falling behind on their bills.

Some have had their smart meters remotely switched over, while others have been confronted by energy firm staff turning up on their doorstep with court orders to enter their homes. 

At the weekend, Business Secretary Grant Shapps warned suppliers to stop carrying out the practice or they would be “named and shamed.”

Ofgem chief executive Jonathan Brearley said in a blog yesterday that he was concerned by the “extremely high” numbers of forced prepayment meter installations. 

“It is simply not acceptable that vulnerable customers are left in the dark and cold in winter,” he wrote. 

“Therefore, today, we will take forward a further, more detailed assessment to check whether plans have led to improvements.

“This review will focus specifically on self-disconnections, remote switching and forced installations and the checks and balances companies have around any decision to put a customer on a pre-payment meter.

“If we find that they have not taken due care in this process, we will take further legal action against them.”

Under current rules, energy firms are not allowed to forcibly move customers onto prepayment meters without first looking at what financial help is on offer or carrying out appropriate assessments.