The Queen, Prime Minister Theresa May and former premier Tony Blair were among those paying tribute to the Armed Forces personnel and civilians who served their country during the Gulf War and conflicts in Iraq and Afghanistan.
The monarch was joined by the Duke of Edinburgh, the Duke and Duchess of Cambridge, Prince Harry, the Prince of Wales and the Duchess of Cornwall for the moving service at Horse Guards Parade in central London ahead of the unveiling of a national memorial.
Former prime minister Sir John Major, David Cameron and Mr Blair - under whose leadership the conflicts were fought - also attended, along with other senior ministers:
Around 2,500 guests including veterans and their families, charity workers and civil servants were also at the service, which has been overshadowed by strong criticism from some military widows who were not invited or informed about the event.
The day began just half a mile away from the memorial, at Horse Guards Parade:
As veterans, serving personnel and their families waited for the service to begin they listened to military bands played on Horse Guards Parade and watched the Drumhead altar being built, with Army colours draped on top.
Excited children, dressed smartly for the important occasion, waited patiently for the royal guests, before standing with their parents as the Queen arrived shortly before the start at 11am:
The service was led by the Chaplain of the Fleet, the Venerable Ian Wheatley, who gave thanks to the civilians and military personnel who served in the Gulf region, Iraq and Afghanistan. He said:
"We pray for all who in bereavement, disability and pain continue to suffer the consequences of fighting and terror. And we remember with thanksgiving and sorrow those whose lives in wars and conflicts, past and present, have been given and taken away."
Prince Harry marked a sombre tribute to the start of the ceremony, quoting "A time to love and a time to hate; A time for war and a time for peace," from the Bible, as acting and former servicemen watched on.
All the wars commemorated on the sculpture remain in recent memory for many. Some of those who served and took part in the conflicts have been telling Forces News what the memorial means to them:
The Defence Secretary, Sir Michael Fallon, said:
"It is vital that we recognise our Armed Forces and civilians who contributed, both abroad and at home, to the campaigns in the Gulf, Iraq and Afghanistan. Today’s service is an appropriate occasion to honour their immense efforts and sacrifices.
"We should also reflect on the continued service of the men and women of our Armed Forces deployed around the world today to help make us safer at home."