Tony Blair believes that the next fortnight could be the last chance for the west to agree a peace deal with Russia to end the Ukraine invasion before the conflict escalates. The former prime minister said that Nato should not rule out intervening in the war but has also called on the west to not give up on the prospect of negotiating a peace deal with Vladimir Putin. Moscow and Ukraine officials held a further round of talks on Tuesday in an attempt to end the conflict which has entered its 20th day. In a lengthy essay on his thinktank’s website, Blair believes that the next two weeks may be the last chance to agree a negotiated settlement “before the assault on Kyiv becomes worse, the Ukrainian people become hostile to any negotiation, or Putin faces a binary choice between “‘double down’ or retreat”. He wrote: “And we should not underestimate the real economic price the world will pay for continued conflict with steep rises in fuel prices, food prices, global trade and inflation, as ever hitting the poorest in our society the worst …” The former Labour prime minister also believes that it is a mistake for Nato to be as specific as it has been about not getting involved in the conflict. He argued that the future status of Crimea and parts of eastern Ukraine could be part of successfully brokering a peace deal with the Russian president. Blair – who served as prime minister between 1997 and 2007 and took the decision for the UK to join the 2003 Iraq war – said that he understands and accepts there is not any political support for direct military engagement by Nato but the west should be “clear-eyed about what Putin is doing.” He wrote: “He is using our correct desire not to provoke escalation alongside his willingness to escalate as a bargaining chip against us. “When he is threatening Nato, even stoking fears of nuclear conflict, in pursuit of his attempt to topple by force a peaceful nation’s democratically elected president and wage war on its people, there is something incongruous about our repeated reassurance to him that we will not react with force. “I accept the reasoning behind our stance. But suppose he uses chemical weapons or a tactical nuclear weapon, or tries to destroy Kyiv as he did Aleppo in Syria, without any regard to the loss of civilian life – is it sensible to tell him in advance that whatever he does militarily, we will rule out any form of military response? “Maybe that is our position and maybe that is the right position, but continually signalling it, and removing doubt in his mind, is a strange tactic.”