Defence Secretary Ben Wallace today poured cold water on claims the UK is poised to send fighter jets to Ukraine.
The Government faces mounting calls to send warplanes to Kyiv as Russia prepares for a renewed spring offensive.
Ukrainian President Volodymyr Zelensky demanded “wings from freedom” when he addressed peers and MPs in Westminster Hall last week.
But speaking from NATO headquarters in Brussels, Mr Wallace said: “You can’t just tow an aircraft to the border and say, ‘Fill your boots, try and jump in this aircraft’.”
He added: “These are weapons systems that potentially take years to train.
“Our own pilots, I think, take five years to train in a Typhoon from scratch, but also if you’re going to fly them properly.
“Secondly, they come with a pit crew. I compare this to a Formula One team - without a pit crew a Formula One car can’t start and it basically falls apart after about 800 miles.
“If you were gifting fighter planes you’d probably have to gift 200 RAF personnel - and we’re not going to put those people in Ukraine - and you then have to train hundreds of people in Ukraine to look after a particular type of jet.”
Quizzed about a timetable for supplying aircraft, he said: “I don't think it's going to be in the next few months or even years that we are going to necessarily hand over fighter jets.”
NATO Secretary-General Jes Stoltenberg said Ukraine “has a window of opportunity to tip the balance” in the war “and time is of the essence” for increasing arms’ supplies to Kyiv.
Former Norwegian Prime Minister Mr Stoltenberg said defence ministers have pledged more heavy weapons and to provide more military training for Ukrainian forces.
But countries also needed to replenish their own ammunition stocks, he warned.
“NATO allies are providing unprecedented support to help Ukraine push back against Russia’s aggression,” he said.
“At the same time, this is consuming an enormous quantity of allied ammunition and depleting our stockpiles.
“Allies agreed on the need to work hand in hand with the defence industry to ramp up our industrial capacity.”
He said the coalition was “reviewing NATO capability targets for munition stockpiles” - paving the way for the alliance to agree to keep more weapons in countries’ caches.
