Veteran suicides are to be recorded in England and Wales for the first time.
The data will be used to better understand where there is a need for dedicated services and ensure they are signposted to veterans where they are most needed, the Office for Veterans' Affairs said.
Currently, data on veteran suicide is drawn from research projects examining specific ex-military cohorts.
Plans to replicate England and Wales' recording of veteran suicides in Scotland and Northern Ireland are being looked into.
Minister for Defence People and Veterans Leo Docherty said: "Any suicide is a tragedy and collecting better data on these instances will help Government better target support for those who need it.
"This builds on a number of studies which are already taking place to better understand why some veterans take their lives.
"Support is out there and I hope that today's agreement will help us reach more people who may be struggling," he added.
The new reporting method will use data collected from the recent veterans question in the 2021 Census and match it with Office for National Statistics-held data on suicides.
It will allow the Government to produce a statistic on the total number of veterans who die by suicide each year.
It is expected the first annual statistics will be published in 2023.
To gain a better understanding of the lives lost prior to 2022, the Government said it will also conduct a 10-year look back to examine veteran deaths through suicide, with research to be published next year.
Watch: The NHS launched a new mental health service for veterans earlier this year – Op Courage.
In March 2020, then-defence minister Johnny Mercer MP said governments had "not acted fast enough to update our data and understanding of military suicide".
Speaking amid a spike in veteran suicides, Mr Mercer said it was not an "epidemic" but that "one is too many", adding suicide rates were lower among veterans than the general population and deaths from suicide among veterans were lower at the time than in the 1990s.
Figures released by the Ministry of Defence, also in March last year, revealed the number of suicides among serving military personnel had slightly increased over the last five years.
Speaking about the new recording of veteran suicides, Hannah Blythyn, Wales' Deputy Minister for Social Partnerships, including veterans' support, said "one life lost is always one too many".
"Their service for our country has enabled us to live in the safe communities we have today.
"Preventing suicide is complex and no one organisation can tackle the issues in isolation. Strengthening the data is a key element of helping us to understand the risk factors and to better target preventative approaches."
Shadow Armed Forces minister Stephen Morgan has been pushing for the Government to make recording suicide among the UK military compulsory for more than two years.
In 2019, he said: "The fact that the figures are currently not readily available for public scrutiny is a danger to service people and our democracy."
In September 2020, on Suicide Prevention Day, he tweeted that "government must commit coroners to recording veteran suicide to pave the way for bespoke mental health support."
And in March, the NHS launched a new mental health service for veterans called 'Op Courage', designed to provide specialist care for ex-military personnel.
Veterans in England who may be struggling with their mental health are encouraged to contact Op Courage.
Veterans in Wales, Scotland and Northern Ireland are urged to contact Veteran NHS Wales, Veterans First Point and the Northern Ireland Veterans' Support Office, respectively.
If you feel you need help or support, click here for direct links to support groups and organisations.