Ukraine's President Volodymyr Zelensky has made a shock visit to the UK where he hailed the bravery of Britain in backing Ukraine against Russian aggression.
The heroic war leader vowed that "freedom will win" and said victory over Russia would "change the world" in his first visit to London since Vladimir Putin's brutal invasion began nearly a year ago.
He used a speech to Parliament to make a plea for warplanes to help Ukrainian troops repel Russian invaders.
Hundreds of MPs, peers, staff and journalists applauded and cheered as he arrived in the historic Westminster Hall to make a speech, the first foreign leader to do so since ex-US President Barack Obama gave a speech there in 2011.
In a passionate address, Mr Zelensky praised the "brave souls" of the UK for their support on behalf of his people.
"I have come here and stand before you on behalf of the brave, on behalf of our war heroes who are now in the trenches under enemy artillery fire," he said.
"On behalf of our air gunners, and every defender of the sky who protects Ukraine against enemy aircraft and missiles, on behalf of our tank men who fight to restore our Ukrainian borders, on behalf of our conscripts who are being trained now including here in Britain."
Mr Zelensky said London had "stood with Kyiv since day one" and he praised ex-PM Boris Johnson, who was in the audience, for helping to unite allies when "it seemed impossible".
His speech was repeatedly met with applause ringing through ancient hall as he said: "We know freedom will win.
"We know Russia will lose. And the victory will change the world - a change the world has long needed."
Ahead of the visit, the Prime Minister announced plans to train Ukrainian pilots to allow them to fly sophisticated NATO-standard fighter jets - a key demand from Ukraine.
The Ukrainian leader used his speech to strengthen his pleas for the West to provide fighter jets for his forces, saying: "I appeal to you and the world with simple and yet most important words: combat aircraft for Ukraine, wings for freedom."
He gave a nod to the Royal Family's military background, saying: "The King is an Air Force pilot. And in Ukraine today, every Air Force pilot is a King.”
Mr Zelensky then gave Commons Speaker Sir Lindsay Hoyle a helmet, used by one of the country's most successful pilots.
On the side were the words: "We have freedom - give us wings to protect it."
The UK and other Western countries have so far rejected demands to gift warplanes to Kyiv to help repel the Russians.
But Mr Zelensky wrapped up his speech by thanking Britain "in advance" for fighter jets.
He told the audience: "Thank you for your attention, thank you for your support. And leaving British Parliament two years ago I thanked you for delicious English tea.
"And I will be leaving the Parliament today thanking all of you in advance for powerful English planes."
The comment prompted laughter among the MPs and peers gathered in Westminster Hall.
The Ukrainian leader wove through the crowds shaking hands with MPs, including Keir Starmer, ex-PM's Liz Truss and Theresa May and his old friend Boris Johnson.
Mr Johnson piled pressure on No10 by putting a statement shortly after the speech saying the UK should give Ukraine more military supplies.
The ex-PM 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.
"We have more than 100 Typhoon jets. We have more than 100 Challenger 2 tanks.
"The best single use for any of these items is to deploy them now for the protection of the Ukrainians - not least because that is how we guarantee our own long-term security."
No10 said Defence Secretary Ben Wallace has been asked to look at whether to send jets but it was a "long-term solution".
The first Ukrainian pilots are expected to come for training in the Spring, the PM's spokesman said.
The remarkable address came in Mr Zelensky's second overseas visit since the war began after he made a whirlwind trip to the United States in December.
He touched down at Stansted Airport at 10.22am for the surprise trip, where he was met on the tarmac by Mr Sunak.
The pair travelled to London in a motorcade and walked up Downing Street together where a red carpet was laid out.
Applause could be heard from staff behind the famous black door as Mr Zelensky arrived, which is highly unusual when a foreign leader visits No10.
Standing in front of UK and Ukrainian flags in No10's White Room, the Ukrainian President said: "Thank you so much Rishi for inviting me and for me great honour to be here in Britain.
"And thanks Britain for society first of all for your big support from the first days of full-scale invasion."
Mr Zelensky said the two leaders would continue their dialogue which he said was "very important for security of our country and of the course the security for the world".
The PM said the pair had had a "good chat" and would discuss how the UK can continue to support Ukraine in the battle against Russia.
He added: "It's a privilege to have you here, Volodymyr. We want to stand by you throughout this conflict and ensure that you're victorious."
Mr Zelensky was also invited to an audience with King Charles at Buckingham Palace.
Pictures show the King greeting him with a smile and a warm handshake in the Palace's 1844 Room.
Mr Zelensky will later visit Ukrainian troops being trained in Britain.
The expansion of the UK's training programme to include jet fighter pilots is a significant move as Ukraine has been urging Western nations to supply planes.
The UK has so far refused, arguing that the RAF's F-35 and Typhoon jets take too long for pilots to train on.
Ukrainian troops are already being trained in the use of Challenger 2 tanks, which are expected to be sent to the country next month.
Mr Sunak will offer longer-range firepower to help counter Russia's ability to strike at Ukraine's towns and energy facilities.
The Prime Minister said: “President Zelensky’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."
It comes as Foreign Secretary James Cleverly unveiled a fresh package of sanctions against the Russian military and Kremlin elites.
Six entities providing military equipment such as drones and helicopters to Russia have been slapped with sanctions.
The Foreign Office said that the sanctions also targeted five individuals linked to Vladimir Putin's luxury residences, including presidential commissioner for entrepreneur's rights Boris Titov and Aerostart owner Viktor Myachin.
Mr Sunak travelled to Kyiv in November only weeks after he became Prime Minister.
