More than 1,300 homeless people died across the UK last year, according to research by a social justice group.
The Museum of Homelessness said the figure of 1,313 in 2022 was up by 85% since its work began four years ago.
The group has been running the Dying Homeless Project since 2019 and said it uses information from coroners’ enquiries, media coverage, family testimony and freedom of information requests to verify details of each case.
It said the aim is to honour and remember people “who would so often be forgotten”.
According to its research, the group said deaths in England rose 22% on 2021 to 875 in 2022, and by 27% in Wales to 76.
The number of deaths in Northern Ireland fell by more than a third to 205 but remains almost double the level seen in 2020.
Scotland recorded a 15% decrease on 2021, with 157 fatalities in 2022.
Researchers said the true numbers are likely to be higher as some local authorities have not contributed to the project over the last two years.
They added that the vast majority of the deaths in 2022 took place after the person was placed in some form of homelessness accommodation rather than when rough sleeping.
Museum of Homelessness director Matt Turtle called for “far stronger policy and investment” in order to deal with the “appalling loss of life”.
He added: “With a heavy heart we expect to report more of the same in 2024, but with our colleagues we will continue to do what we can to save lives.”
Separately, the project has for the first time obtained figures suggesting the number of deaths that occurred in exempt accommodation – a type of supported housing for residents with specific needs that is exempt from local caps on housing benefit.
Of the 12 local authorities who responded to the Museum of Homelessness request for information, Manchester reported 109 deaths in exempt accommodation across 98 properties.
This compared to 21 deaths among the rest of the homeless population in Manchester, researchers said.
The total deaths in exempt accommodation across 12 local authorities in England was 151. The others were Hull (7), Mansfield (5), Mid Devon (1), Middlesbrough (6), Rotherham (4), Sandwell (1), Sunderland (1), Sutton (2), West Northamptonshire (4), Durham (1), Kensington and Chelsea (10).
Mr Turtle said: “The fact that so many people continue to die in unregulated, taxpayer-funded accommodation run by rogue landlords is a disgrace.
“The upcoming Supported Housing (regulatory oversight) Bill will provide an urgently needed framework to regulate the rogues but it’s clear local authorities won’t have the resources they need to implement it.
“The Government needs to move past piecemeal measures to address both the immediate crisis and the lack of social housing that causes it.”
In October a damning report from the cross-party Levelling Up, Housing and Communities Committee warned that the exempt housing system in England is a “complete mess” that lets down vulnerable residents and rips off taxpayers.
It said vulnerable people in need of support are being exploited while providers make excessive profits by capitalising on loopholes.
The Museum of Homelessness and frontline groups including the Simon Community, Streets Kitchen and The Outside Project are hosting a vigil outside Downing Street on Thursday evening and are encouraging people to light a candle at home and post a picture online with the hashtag #MakeThemCount.
The next release by the Office for National Statistics of homeless deaths registered in England and Wales in 2022 is due in November.
A spokesperson for the Department for Levelling Up, Housing and Communities said its plan to tackle homelessness and rough sleeping “includes £186 million to help those with drug and alcohol addiction access recovery services and up to £53m for suitable and stable accommodation”.
They added: “Councils have a duty to ensure temporary accommodation is suitable and we are providing them with £654m over two years to help prevent homelessness.”