More than 700,000 households in Great Britain have missed out on energy bill support, despite being eligible for it, according to a new analysis.
In February, the government said more than 900,000 households in places such as park homes and houseboats could get a one-off £400 payment - even though they did not have an energy supplier that could apply it automatically.
But government figures show that only about 200,000 applications were made before the deadline on May 31.
Data from the Department for Energy Security and Net Zero shows that almost 125,000 had already been paid by the beginning of June, and 6,000 more had been approved but not paid yet.
A further 13,000 applications were on hold or being validated by local councils, while around 60,000 were rejected or cancelled, reports the BBC.
Mark, who lives in a narrowboat and uses three and a half bags of coal for his multi-fuel stove each week in winter, previously paid around £9 per bag but last winter he saw the price nearly doubling.
However, he said he was not eligible for the payment as he lives off-grid, as he explained: "[The £400 payment] would've been a great help. That money's had to come from somewhere so it's had to come out of the rest of my budgeting or my savings.
"It would've made my winter a bit easier, maybe I could have spent a bit more money on the grandkids."
Carol, who lives on a park home site southeast of Runcorn, Cheshire, said the application process was simple but she had to apply three or four times as she kept being rejected.
She said: "We got refused, I don't know how many times. I kept going, I wouldn't give up. Because I thought, 'Why should I give up?' I've worked all my life, I've paid into the system.
"[The £400] was very important because 99.9% of people on these sites are all retired and a lot of them only have a basic pension, or maybe a bit of a top-up pension."
It comes as Martin Lewis this week shared an update about the energy market that could save Brits some money.
On Friday, the MoneySavingExpert.com website posted an article that highlighted Ofgem's new request for energy suppliers to publish details about all of their energy tariffs.
The move, which came from a campaign from Martin Lewis, intends to make it easier for customers to see and understand whether a fixed deal is worth switching to.
Before, energy providers did not need to share the tariffs they offer to existing customers which meant customers couldn't accurately compare whether it was cheaper to move.
Martin first raised this issue with Ofgem several months ago, and followed it up with a formal letter last month.
The MSE founder said under the current rules, it was "near-impossible" for consumer advice organisations to provide guidance over the "opaque" deals that suppliers offer customers.
He explained that his consumer guidance website, Money Saving Expert, had to “rely on crowdsourcing from consumers willing to forward bills”.
He added that as energy suppliers were now bringing back "short-lived competitive fixed deals" he said it "urgently" needed to be addressed.
This week, Ofgem announced that it had requested that all energy firms needed to set out "clear expectations" on financial resilience and how they should support consumers going forward.
The energy regulator said it will be "monitoring" the situation to make sure the market was operating "competitively" on price.
As a first step, it requested suppliers to publish all their domestic tariffs.