Boris Johnson and other NATO governments have faced criticism for ruling out a no-fly zone, however Sir Simon gave a stark warning on BBC Newsnight that doing so would equate to an “act of war”. Russia has been hit hard by economic sanctions but NATO Secretary General Jens Stoltenberg told NBC the alliance had “no intention of moving into Ukraine, either on the ground or in the air”.
There are fears such a move could lead to full-scale war in Europe.
Sir Simon said: “This is a key disagreeable fact from the point of view of Ukraine but an immovable fact.
“The alliance, NATO, is doing all it can to help, but a no-fly zone would take on Russia in a direct way.
“A no-fly zone would require Western planes to shoot down Russian planes, that would be an act of war.
“That would be a general conflagration very soon.
“It’s tragic, but there are limits to what we can do.”
Tobias Ellwood MP, who chairs the Defence Committee, is in favour of a no-fly zone as Russian airstrikes are causing civilian deaths in Ukraine.
However, Defence Secretary Ben Wallace told Radio 4’s Today programme that Britain would not enforce a no-fly zone over Ukraine due to the threat of war.
Boris Johnson said at a press conference on Tuesday that implementing a no-fly zone was “not something that we can do or that we’ve envisaged.”
He added: “The consequences of that would be truly very, very difficult to control.”
He faced impassioned pleas from Daria Kaleniuk, the Ukrainian executive director of Anti-Corruption Action Centre civil society organisation to do more to help Ukrainian citizens by imposing a no-fly zone.
She said: “Ukrainian children, Ukrainian hospitals will be hit with missiles and bombs”.