There is no telling how high household energy bills could rise this year, the boss of one of the biggest energy firms has said.
Greg Jackson, chief executive of Octopus Energy, told the BBC "we don't know yet" when asked how expensive gas and electricity costs could become when the price cap is reviewed.
Octopus is one of the 'big six' UK energy companies.
The price cap limits how much energy firms can charge households on default tariffs for average energy use every year.
This cap is currently £1,277 for those on default tariffs and £1,309 for those on pre-payment deals.
But the cap is reviewed twice a year by the Ofgem energy regulator, with the next change coming in April.
Jackson said energy companies were working hard "minimise cost increases".
Are you seeing big hikes in your energy bills? Message mirror.money.saving@mirror.co.uk
Jackson told the BBC Today programme: "The reality is that in the energy sector, the UK buys most of its energy on a global market and we've had to pay about £20billion more than usual this year.
"So in one way or another, the UK's going to have to pay that money."
Energy UK chief executive Emma Pinchbeck has warned that "domestic energy prices are going to go up 45% to 50% in the spring".
According to another expert, energy sector specialist Cornwall Insights, bills could rise by 46% as the price cap could rise to £1,865 a year.
It is widely expected that Ofgem will raise the cap in April, meaning households pay more.
This is because the cost of gas has soared, and energy providers say the price cap means they have to sell energy for far less than it costs them to supply.
Many energy firms have been unable to take the extra strain and have been forced to stop trading.
Several 'big six' energy companies have been pushing the government to scrap the cap completely.
Yesterday The Mirror reported that Together Energy is the latest provider to face collapse as it struggles to find new funding.
The Scottish-based energy firm, which has 170,000 customers, could run out of cash by the end of this month if it cannot find a new source.
All of Together Energy's power comes from renewable sources, and 90 percent of its staff come from the 10 percent of poorest postcodes in Scotland.
What to do if your energy firm stops trading
If your energy firm collapses, the advice from Ofgem is to sit tight and wait until your new supplier contacts you.
You should wait until you know which firm you've been moved to before you decide to look into switching elsewhere .
In the meantime, take a meter reading for when your new supplier contacts you so it can correctly bill you.
It is important to check prices as soon as you know which deal you've been moved to, as you may not necessarily be transferred over to the cheapest supplier.
You won't be charged exit fees for switching away from your new energy provider.
