One of the Big Six energy companies has warned a potential energy price cap could harm competition.

The comment from Keith Anderson, Chief Corporate Officer at ScottishPower, comes amid speculation the Conservative Party is planning to cap household energy prices as part of its manifesto.

He suggests the government could instead set a deadline to abolish Standard Variable Tariffs (SVT) and get every customer on a fixed-price deal instead.

ScottishPower had initially made the recommendation to the competition watchdog two years ago.

Mr Anderson added: “Just as you insure your car every year and go to the market for the best deal for you, so every energy customer should engage with the market at least once a year to make sure they are on the best deal for them.

“The government could impose a target that two out of three customers should be on a deal by the end of 2018 and all customers on a deal by the end of 2019 with SVT abolished once and for all. Any company that fails to meet these targets should have a price cap not only imposed but retained until all their customers are on deals.”

Last week ScottishPower announced a 28% fall in pre-tax profits in the first quarter of this year.