Emmanuel Macron, the French president, ruled out sending tanks and warplanes to Ukraine, while Boris Johnson said: “Logistically at the moment, it looks very difficult both with armour and with jets.”

Last month, Poland offered to provide Ukraine with 28 MiG jets, sent via an American air base in Germany, but the US pulled the plug, fearful that it could drag Nato into direct conflict with Russia.

“The worst thing during the war is not having clear answers to requests for help,” Mr Zelensky said.

Now though, the prevailing mood in Washington and elsewhere is that the West needs to get “on the front foot”, as one diplomat told the Telegraph.

Germany has approved the delivery of several dozen infantry fighting vehicles amid criticism that Berlin has not been sending enough military aid to Kyiv.

Nato allies will also discuss the delivery of more weapons to Ukraine when foreign ministers meet on Wednesday and Thursday, Jens Stoltenber, the alliance’s secretary-general, said.

The Ukrainian army is trained to use soviet vehicles, so the UK is not expected to supply British tanks. However, the UK could act as a facilitator for other allied nations to supply them to Kyiv.