Emmanuel Macron, the French president, has continued to keep lines of communication open to Vladimir Putin since the beginning of the invasion, arguing that he could help negotiate a solution to the fighting.
German Chancellor Olaf Scholz has taken a tougher line with Putin than his predecessor Angela Merkel, including rising defense spending and declining Russian energy imports.
But Germany remains much more dependent on Russian oil and gas than the United Kingdom, and German officials have been accused at times of delays in imposing harsh sanctions on Moscow since the invasion.
The government’s main source said of Mr Johnson and the Allies’ approach to Ukraine: “His fear is that there will be a lot of war fatigue.”