The former prime ministers have joined a campaign – along with leading names from the worlds of from law, academia and politics – aiming to put the Russian president on trial alongside those who helped plan his invasion of 24 February.
Launched with a website and a target of two million petition signatures, the campaign – already backed by 740,000 people around the glove – seeks to gain public support for a special tribunal modelled on the Nuremberg trials.
The proposal already has more than 140 signatories, including both former prime ministers, Ukrainian foreign minister Dmytro Koleba, leading professor of international law Philippe Sands QC, former prosecutor for the Nuremberg Military Tribunals Benjamin Ferencz, Helena Kennedy QC and former president of the European Court of Human Rights (ECHR) Sir Nicolas Bratza.
Mr Brown said: “In only two days, the petition supporting the tribunal has already secured well over 735,000 signatures and growing. Let us aim to get two million signatures for justice by the end of the month.
“From Britain – which rightly prides itself in democracy and the rule of law – the message must go out. At Nuremberg, we held the Nazi war criminals to account. Now, eight decades on, we must ensure there will be a day of reckoning for Putin.
“I urge everyone to sign this petition.”