The Ukrainian president has asked for air support from the UK and other Western nations, ITV News' Rohit Kachroo reports
The UK is "actively" considering whether to supply Ukraine with fighter jets after a plea from President Volodymyr Zelenskyy for "powerful English planes".
Rishi Sunak's spokesman said no decision had been made on whether to grant Mr Zelenskyy's wish and insisted jets would only form a "long-term solution rather than a short-term capability, which is what Ukraine needs most now".
Asked about the possibility of sending jets to Ukraine during a joint press conference with Mr Zelenskyy in Dorset, Prime Minister Sunak said "nothing is off the table".
Mr Zelenskyy asked for air support from the UK and other Western nations, in an earlier speech at Westminster Hall during his first visit to Britain since Russia invaded his country.
The UK and the rest of Nato have been refusing to send military jets to Ukraine, arguing that the RAF’s F-35 and Typhoon aircraft systems take too long for pilots learn. However, the president's visit may have sparked a shifting of the dial, in Britain at least.
Asked following Mr Zelenskyy's speech whether fighter jets would be provided, the PM's spokesman said Britain had already promised to train Ukrainian pilots, but added: “What we have not made a decision on is whether we send UK fighter jets."
"Obviously there is an ongoing discussion among other countries about their own fighter jets, some of which are more akin to what Ukrainian pilots are used to.”
He continued: “We’ve confirmed there will be a training programme for Ukrainian pilots and the Defence Secretary [Ben Wallace] is actively looking at whether we send jets.”
President Zelenskyy poured praise on Britain for its support of Ukraine in his speech, saying "the world needs your leadership Britain, just as it needs Ukrainian bravery".
He said: “London has stood with Kyiv since day one, from the first seconds and minutes of the full-scale war, Great Britain you extended your helping hand when the world had not yet come to understand how to react."
In a powerful, symbolic gesture, the Ukrainian president gifted House of Commons Speaker Lindsay Hoyle the helmet of a fighter pilot, on which were written the words: "We have freedom, give us wings to protect it."
Much of his rousing speech was used to request jets - a plea the West has treat with caution, given Vladimir Putin has a nuclear arsenal at his disposal and has previously threatened to use it if an attack is launched on Russian soil.
But former prime minister Boris Johnson appears to believe the benefit of supplying the jets outweighs the risk.
He said: “It is time to give the Ukrainians the extra equipment they need to defeat Putin and to restore peace to Ukraine.
“That means longer range missiles and artillery. It means more tanks. It means planes."
He added: “Every time we have stepped up with more military support the Ukrainians have responded and turned the tide of war. Now is the time to give them exactly what they need to finish the job.”
Sunak and Zelenskyy chat in Downing Street on the Ukrainian's first UK visit
Mr Zelenskyy has also been meeting Ukrainian troops in the South West, who are being trained by the British armed forces.
The government said the training will "ensure Ukraine can defend its skies well into the future".
Britain is one of the biggest military backers of Ukraine and has sent the country more than £2 billion in weapons and equipment.
More than 10,000 Ukrainian troops have also been trained at bases in the UK, some on the Challenger 2 tanks that Britain is sending.
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Mr Zelenskyy's visit is only his second known trip outside of Ukraine since Vladimir Putin's Russia invaded, with the first being a summit in the US.
His first address to the UK Parliament was a virtual one, in March last year, in which he echoed Winston Churchill’s famous “never surrender” speech, vowing that Ukrainians “will fight till the end at sea, in the air. We will continue fighting for our land, whatever the cost".
The PM said: “President Zelenskyy’s visit to the UK is a testament to his country’s courage, determination and fight, and a testament to the unbreakable friendship between our two countries.
“Since 2014, the UK has provided vital training to Ukrainian forces, allowing them to defend their country, protect their sovereignty and fight for their territory.
“I am proud that today we will expand that training from soldiers to marines and fighter jet pilots, ensuring Ukraine has a military able to defend its interests well into the future.
“It also underlines our commitment to not just provide military equipment for the short term, but a long-term pledge to stand shoulder-to-shoulder with Ukraine for years to come.”
Mr Sunak visited Ukraine recently in November, with Mr Zelenskyy praising a “meaningful and useful visit for both our countries”.
“With friends like you by our side, we are confident in our victory,” he added on Twitter.
The UK has also announced new sanctions targeting those who have helped Vladimir Putin build his personal wealth and firms which have profited from the war.
Ukrainian troops are already being trained in the use of Challenger 2 tanks, which are expected to be sent to the country next month.
Sunak also offered longer-range firepower to help counter Russia’s ability to strike at Ukraine’s towns and energy facilities.After the speech Mr Zelenskyy headed to Buckingham Palace for a meeting with King Charles.
The pair were served tea during 30 minutes of conversation about the continuing conflict in Ukraine, and the part Britain has played in supporting the nation.
Mr Zelenskyy said it was an honour to be at the palace and the King told him "we’ve all been worried about you and thinking about your country for so long, I can’t tell you".
After finishing his engagements in London, Mr Zelenskyy flew to Paris for dinner with French President Emmanuel Macron and German Chancellor Olaf Scholz.Mr Zelenskyy was greeted Wednesday night on the steps of the Elysee Palace with a friendly embrace by Mr Macron, and then all three leaders headed inside.
The visit marks a turnaround in Mr Zelenskyy’s relations toward France and Germany, which earlier in the war were viewed by many in Ukraine as not doing enough to help.
"Ukraine can count on France, its European partners and allies to win the war. Russia cannot and must not win," Mr Macron said before their working dinner.