Speaking after his keynote speech, Sir Keir Starmer said Boris Johnson has not “earned the right” to be given a knighthood after he leaves office.
Asked if the Prime Minister should receive an honour in future, as former prime minister Tony Blair has this year, Sir Keir said: “No, I am sorry, I don’t think that this Prime Minister has earned the right to have an honour.
“I do think Tony Blair has.”
This comes after a petition started on New Year's Day to remove Tony Blair's knighthood has now reached over 569,902 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:
''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.'
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.