Events in Ypres, Belgium, will be held in July to mark the centenary of Passchendaele, one of the muddiest and bloodiest battles of World War One.
Descendants of British soldiers who fought in the battle will be offered free tickets to the commemorations.
About 325,000 Allied troops and 260,000 Germans died in the battle.
Culture Secretary Karen Bradley said it was important to remember the “horrors” of the Ypres battlefields, and honour the memories of the many who died.
Officially known as the Third Battle of Ypres, Passchendaele was fought from 31 July to 6 November 1917 in the West Flanders region of northern Belgium.
It is remembered as one of the harshest battles of the war, with heavy rain contributing to the Allies gaining only five miles of ground in three months. It was also the first time poison gas was used on the Western front.
Poet Siegfried Sassoon described the muddy fields as “hell”.
Ms Bradley said: “Some of World War One’s most defining images of futility, mud, gas attacks and trenches come from these very battlefields.
“As the war recedes into the distance, it is our responsibility to not only mark the years that have gone past, but to keep alive the memories of those who sacrificed so much.”
The main ceremony will be on 31 July at the Commonwealth War Graves Commission’s Tyne Cot Cemetery, where 12,000 British and Commonwealth troops are buried.
There will also be a traditional Last Post ceremony at the Menin Gate memorial in Ypres on 30 July and a number of live performances in Ypres’ Market Square to tell the story.
The 4,000 tickets to the 31 July event at the cemetery will be available through a public ballot online at www.passchendaele100.org until 24 February.
There will also be a smaller ballot for a limited number of tickets for the event at the Menin Gate memorial.
Both events will be shown on large screens in the centre of Ypres for those who do not get tickets.
Ms Bradley said she encouraged all of those with family who fought at Passchendaele to apply.
Paul Breyne, the Belgian general commissioner for the commemoration, said his government was deeply committed to supporting the commemoration.
It was of utmost importance to remember those who “made the ultimate sacrifice for our freedom and peace”, he said.
He said Belgium was looking forward to welcoming those who were travelling “to pay tribute to those who fought with dedication and bravery, 100 years ago, in this devastating battle”.