A memorial dedicated to those who served in Afghanistan and both Iraq wars will be unveiled by the Queen in central London on Thursday.
The sculpture by Paul Day also marks the contribution made by civilians in the conflicts. It is formed of two stone monoliths and a bronze medallion.
Its unveiling in Victoria Embankment Gardens will follow a service for 2,500 veterans on Horse Guards Parade.
More than 800 UK military personnel and civilians died in the three wars.
- Forty-seven members of the armed forces died in Iraq in the 1990-91 conflict
- 179 were killed in the second Iraq war from 2003-09
- and 456 died in Afghanistan between 2001-14
- In addition, 43 UK civilians were killed in the second Iraq war
- and 101 in Afghanistan
The Queen and other members of the Royal Family will attend a “drumhead” service – a religious service held in the field of battle which uses drums as an improvised altar – with veterans and other guests.
Prince Harry served in the Army for 10 years, including two tours of Afghanistan. Prince William served in the armed forces for eight years.
The guests will include current service personnel, veterans, civil servants and charity workers.
A small ceremony will then be held in the gardens for the unveiling itself. It will be relayed to screens on Horse Guards.
The £1m monument was funded by a campaign by the Sun on Sunday newspaper.
Mark Collins, a former RAF wing commander who did two tours of Afghanistan, said the memorial would be a focal point where people could reflect on the good that went on overseas as well as the sadness.
He said he would remember a US marine from his team who was killed by a suicide bomber, leaving a physical absence in the team as well as frustration and anger for his loss.
He would also be thinking about friends and colleagues who returned from war with physical and mental illnesses, and their families having to cope, he added.
“It’s important that we remember and reflect so we don’t go down those roads again and we learn the lessons,” he told the BBC.
Analysis: Were bereaved families snubbed?
By BBC correspondent Nick Higham
The event has been overshadowed by a row over the failure to include the families of the 682 service personnel who died in Iraq and Afghanistan among the 2,500 invited to the ceremony.
One widow of a soldier killed in Afghanistan said they had been snubbed; another called the decision completely crass.
Liberal Democrat leader Tim Farron called on the prime minister to apologise for what he called a careless oversight.
Mrs May said charities and groups representing the bereaved had been asked to put forward names of attendees.
But the chairman of the War Widows Association told the BBC that while she’d been invited herself she’d not been asked to nominate others, and that the Ministry of Defence should have contacted all the families directly.
I understand that in the past few days the MoD has been doing that though the government points out that the memorial is intended to commemorate all those who served, not just those who died.
Sculptor Paul Day also created the Battle of Britain monument, which stands nearby on the Embankment, the Queen Mother’s memorial statue on the Mall, and the Meeting Place – the sculpture of an embracing couple which greets arrivals from across the channel at St Pancras station.
This design consists of two large stone monoliths which appear to support a bronze medallion.
The Portland stone, quarried from under Portland’s cricket pitch, weighs 33 tonnes.
The stone is finely carved on three sides but left jagged and rough hewn on one, he said: “To suggest the harsh, dry, rocky and difficult terrains of the two countries but also to suggest how the outcomes of both campaigns is not fully resolved, that there was much division within the British people over them.”
Memorial ‘to stand tall’
However, people were united, he added, in support of “what the military and civilians did, in putting themselves in harm’s way, securing British lives and improving the lives of Iraqi and Afghan civilians”.
“An awful lot of amazing stuff has been done and is still being done despite the controversies that have dogged the nation.”
He said he wanted to create something contemporary in the 19ft (almost 6m) structure to reflect the most recent of UK military campaigns and hoped to have made a “fine piece of art” for those who paid the ultimate sacrifice.
“When we unveil it, I want to be able to say I’d put as much thought and effort as possible into the project; to do justice to the price that was paid and to create a memorial that will stand tall in years to come, for future generations, to remember all that was done,” he said.
Defence Secretary Sir Michael Fallon said the memorial would, “stand as a permanent reminder of the contribution and sacrifice that so many members of our Armed Forces, aid workers and civilian personnel made towards the security of the United Kingdom and the interests of Iraq and Afghanistan”.
The Ministry of Defence said it honoured the duty and service of British citizens, including those who worked on the humanitarian side of operations.