A petition started on New Year's Day to remove Tony Blair's knighthood has now reached over 500,625 signatures.
Buckingham Palace said Tony Blair is to be knighted with the highest possible ranking in the new year honours list.
The petition organiser Angus Scott wrote:
Former prime minister Tony Blair arrives at BBC Broadcasting House Victoria Jones
'Sir Tony, who held the keys to No 10 between 1997 and 2007, will be appointed a Knight Companion of the Most Noble Order of the Garter, the oldest and most senior British Order of Chivalry.
'Tony Blair caused irreparable damage to both the constitution of the United Kingdom and to the very fabric of the nation's society.
'He was personally responsible for causing the death of countless innocent, civilian lives and servicement in various conflicts. For this alone he should be held accountable for war crimes.
'Tony Blair is the least deserving person of any public honour, particularly anything awarded by Her Majesty the Queen.
'We petition the Prime Minister to petition Her Majesty to have this honour removed.'
One signatory wrote: "Tony Blair should be prosecuted not knighted. Someone like this being honoured shows how corrupt & vile the system is."
The appointment was made by the Queen in her New Year's Honours list.
Knighting Prime Minister's is not uncommon, with Sir John Major – Sir Tony’s direct predecessor – the last to have the honour bestowed him.
Commons Speaker Sir Lindsay Hoyle has said he thinks every former Prime Minister should receive the honour from the Queen.
He said on BBC Radio 4, “Whatever people might think, it is one of the toughest jobs in the world and I think it is respectful and it is the right thing to do, whether it is to Tony Blair or to David Cameron. They should all be offered that knighthood when they finish as prime minister”
Blair is currently executive chairman of the Tony Blair Institute for Global Change, which states that since leaving office he has been "supporting governments to deliver effectively for their people, working for peace in the Middle East and countering extremism".