Martin Lewis has warned how millions of households could be left out of the energy bill help to be announced by Liz Truss today.
The new Prime Minister looks set to cap energy bills at £2,500 this afternoon.
It is understood Mr Truss will also keep the £400 discount in place and could also do away with green levies - taking energy bills to just above £2,000.
The Ofgem price cap is currently £1,971 for someone on a default tariff who pays by direct debit - but this is set to rise to £3,549 in October.
MoneySavingExpert founder Martin Lewis appeared on the BBC Radio 4 Today Programme this morning to highlight those who are not covered by the Ofgem price cap.
For example, the price cap doesn’t apply to people in Northern Ireland, or those who use heating oil or those
Renters could also fall under the cracks, if they pay their energy direct to their landlord, and people in park homes are also not normally in charge of their gas and electricity bills.
The Government has yet to announce full details of the energy help to come, so it isn't clear just yet what it will mean for every household.
“This helps every household in England, Scotland and Wales who pays a gas and electricity bill,” said Martin.
“Those in Northern Ireland have different energy firms, different regulatory structures.
“Those who have LPG or heating oil - many in rural areas and have seen substantial rises - are not covered by the price cap.
“We also need to make sure the benefits of this policy go to those who pay landlords for energy bills, students who’ve been locked into high prices in anticipation of these rises - because these are people who pay their landlord directly, not an energy company.
“Those with communal heating contracts, those living in park homes.”
There is also an issue for people who have recently locked into a fixed energy deal, in anticipation of rises later this year and into 2023.
There is normally a 14-day cooling off period if you’ve tied yourself into a contract - and these people could risk
“There is a big question about those, who - understandable - have chosen to fix their bills, often at higher levels than the price cap to forestall future rises,” said Martin.
“People have made a legitimate choice to fix their bills.
“What I would call for as a bare minimum is, anyone on a fix should be allowed by every energy company to switch to the state subsidised energy tariff without any exit penalties.”
The price cap sets a limit on the rates a supplier can charge for each unit of gas and electricity you use, as well as the daily standing charge.
It currently covers around 24 million households.
