Key elements of the awe-inspiring Tower of London poppy display are to stay on show until the end of the month, David Cameron has said.
The art project, titled "Blood Swept Lands and Seas of Red," brings 888,246 ceramic poppies to the property of Her Majesty's Royal Palace and Fortress.
Appearing like a blood-red moat around the castle, the poppies pay tribute to the Great War's fallen troops and have so far drawn huge crowds who are keen to view the event.
Huge demand from the public has triggered a campaign to extend the lifespan of the installation by Paul Cummins and Tom Piper and floodlights are already being used to ensure as many people as possible get to see it.
But Historic Royal Palaces, which runs the Tower of London, has said it intends to start dismantling the artwork on November 12 - the day after Armistice Day.
A team of 8,000 volunteers has been lined up to start removing and cleaning ceramic poppies, before dispatching them to buyers who have paid £25 each to raise money for armed forces charities.
Mr Cameron said the installation, created to mark the centenary of the start of the First World War, had become a "much loved and respected monument" in a short space of time. He said the Weeping Window and the Wave would stay in place for longer, before being sent on a tour of sites across the UK until 2018. Finally they will go on permanent display at the Imperial War Museum.
The tour will be funded with donations from the Backstage Trust and the Clore Duffield Foundation, as well as £500,000 from the Government.
"I think the exhibition of the poppies has really caught the public imagination, people have found that incredibly moving," Mr Cameron said. "What we've managed to do is find a way of saving part of the exhibition for the nation and making sure it will be seen by many more people.
"Then it will be permanently saved by the Imperial War Museum - I think the right place for it to be - and something that marks the fact that everybody has found it so moving, so poignant, and such a brilliant idea."
"By displaying parts of the installation around the country and then permanently in the Imperial War Museum, we have ensured that this poignant memorial will be saved for the nation."
Culture Secretary Sajid Javid, who leads the Government's programme to mark the centenary of the war, added: "The poppies at the Tower are a stunning memorial to those who died in the First World War.
"I had the honour of being allowed to plant one of the poppies myself and, like the four million or so people who have gone to see them, I was left in awe at the sheer scale and strength of the piece. For me this is public art at its most powerful and moving."
Chancellor George Osborne said penalty fines paid by banks over the Libor-fixing scandal would be used to fund the tour.
"The Tower of London poppies are a striking reminder of the sacrifice that over 800,000 British and Commonwealth soldiers made to protect our freedom during the First World War, so I'm delighted that £500,000 of Libor fines will be used to ensure that people across the country will be able to see this moving tribute over the next four years," he said.
"To support the current generation of brave servicemen and women who continue to protect our freedoms every day, we're also using Libor fines to waive VAT on the sale of these poppies, with proceeds going to military charities.
"It's only right that fines from those who have demonstrated the very worse of values should go to support those who have shown the best of British values."
General the Lord Dannatt, Constable of the Tower of London, said: "We are delighted that key elements of Blood Swept Lands and Seas of Red - the poppies installation at the Tower of London - which has so captured the heart of the nation, are to be preserved for many more thousands of people to see and appreciate over the coming four years.
"All at the Tower of London and Historic Royal Palaces are most grateful that this wonderful community art project will continue for the next four years."
An online petition had been set up to keep the poppies at Tower of London, and the memory they evoke, for another year.
See how the poppies were made.