A former Russian prime minister has said Vladimir Putin may be forced to agree a peace deal to end the war with Ukraine by the end of the year. Mikhail Kasyanov said Russia’s “contracting” economy meant the country’s president may have no option but to seek a settlement to stop the hostilities.

Putin’s refusal to compromise on Ukraine, analysts say, is a colossal error costing Russia regional influence, lucrative energy markets and its place in the world.