Co-operative Energy and Ebico have become the first two challenger suppliers to announce an increase in prices.

The news follows price rises confirmed by all the Big Six companies – British Gas, E.ON, EDF Energy, Npower, ScottishPower and SSE – after Ofgem announced an increase in the energy price cap for standard variable tariffs to £1,254 a year and prepayment meters to £1,242 from 1st April 2019.

The price rise affects customers on its GB Energy and Flow Energy brands as well.

A spokesperson for Co-op Energy said: “Ofgem announced it was raising the level of the price cap because of the increasing costs faced by energy suppliers. As the UK’s largest member-owned energy supplier, we have a responsibility to run a sustainable, long-term business, which includes ensuring our prices reflect our operating costs."

“We have written to our customers and advised them if they can save money by switching to another tariff.”

Ebico also announced a 16% increase, which will add £169 on average a year to the standard variable tariff, boosting bills from £1,058 to £1,127 a year.

The supplier said it is “continually working” to reduce costs for customers so its energy plans are price below the new cap levels.

It added: “Ebico customers supplied under PrePay energy plan will see an increase in their energy price from the 1st of April and customers supplied under our Standard and Evergreen energy plans will see an increase int heir energy price from the 4th of April. All affected customers will soon receive a letter or if registered for paperless billing, an email, with full details of the changes.

“Customers supplied under one of our 12 or 18-month fixed term energy plans are not affected by these changes.”