Volodymyr Zelenskyy has offered a potentially open-ended ceasefire beginning on Wednesday to Vladimir Putin, whose defence ministry has demanded that hostilities should cease for Friday and Saturday so that Russia can mark the anniversary of the second world war defeat of Nazi Germany, 81 years ago.

The Russian defence ministry threatened that if its truce demand was not met there would be a “massive missile strike on the centre of Kyiv” – adopting a tone akin to Donald Trump’s recent threats to attack Iranian civilian infrastructure, in what has been condemned as a potential war crime.…