LONDON — President Volodymyr Zelensky of Ukraine pleaded with Britain on Wednesday to provide his nation with fighter jets, making his dramatic attraction throughout a shock go to to London that started a two-day diplomatic blitz of Ukraine’s Western allies.

Expressing thanks for Britain’s strong and early navy help, Mr. Zelensky however warned that warplanes had been now urgently wanted to thwart a contemporary Russian offensive that’s already mobilizing in Ukraine’s east.

Thus far, the British authorities has resisted Ukraine’s request, as has the US and different NATO nations, fearing that fight plane might escalate confrontation with Russia. However Prime Minister Rishi Sunak introduced that Britain would practice Ukrainian pilots to fly NATO-standard jets, and signaled he was open to finally sending planes.

“On the subject of fighter fight plane, in fact they’re a part of the dialog,” Mr. Sunak mentioned in a information convention alongside Mr. Zelensky, at a navy base in southern England. “Nothing is off the desk.”

From London, Mr. Zelensky flew to Paris, the place he pressed his case for heavier weapons in a night assembly with President Emmanuel Macron of France and Chancellor Olaf Scholz of Germany on the Élysée Palace.

“The earlier Ukraine will get long-range heavy weaponry, the earlier our pilots get planes, the earlier this Russian aggression will finish and we are able to return to peace in Europe,” Mr. Zelensky mentioned, standing alongside each leaders.

On Thursday, he’s anticipated to look in Brussels for conferences with European Union leaders. All informed, it’s a assured, if plaintive tour, by a pacesetter whose nation stays below deadly each day bombardment by Russian artillery.

Mr. Macron echoed Mr. Sunak’s pledge of help, although with no reference to planes. “It will likely be essential for us to pursue, to adapt and to modulate the navy help that’s essential to protect Ukraine and its future,” he mentioned.

Mr. Zelensky’s purpose of securing fighter jets nonetheless faces formidable hurdles, however that didn’t cease him from making a full-throated entreaty.

“I attraction to you and the world with these most straightforward and but vital phrases,” Mr. Zelensky mentioned to a joint session of Parliament below the traditional, timbered ceiling of Westminster Corridor. “Fight plane for Ukraine, wings for freedom.”

Mr. Zelensky obtained a hero’s welcome in London on a day laden with symbolism. On the airport, he was welcomed with a hug by Mr. Sunak, who then conferred with him at 10 Downing Road. After his handle to Parliament, Mr. Zelensky had an viewers with King Charles III at Buckingham Palace, earlier than flying with Mr. Sunak to the bottom in Dorset, in southern England, to fulfill Ukrainian troops present process coaching.

Mr. Zelensky’s choice to make London the primary cease of his journey, solely his second outdoors Ukraine since Russia invaded final yr, attested to Britain’s function as one of many largest suppliers of weapons to Ukraine, and to the steadfast public help of Mr. Sunak and his predecessors, Liz Truss and Boris Johnson.

Nonetheless, coaching pilots to fly high-tech planes is extra time-consuming and troublesome than coaching troopers to drive tanks. Britain’s likeliest jet for export to Ukraine, the Eurofighter Storm, is difficult to function and keep, navy analysts mentioned.

It’s additionally not clear that Britain has sufficient planes to make a distinction; there are solely about 30 of the older era of the Storm jets that may very well be made out there, in response to Janes, a protection intelligence agency.

Even the function of manned plane on this conflict has been constrained, given the widespread use of missiles and drones, and the effectiveness of Ukraine’s and Russia’s air-defense techniques. For all their symbolic worth, analysts mentioned fighter jets may make much less of a distinction on the battlefield than tanks.

“Sooner or later, it’s worthwhile to ask what Ukraine goes to make use of them for,” mentioned Malcolm Chalmers, deputy director normal of the Royal United Companies Institute, a assume tank in London. “You don’t need extremely refined planes sitting on Ukrainian runways, the place they are often focused by the Russians.”

By signaling its openness to sending fighter planes, nonetheless, Britain might play the identical catalyzing function it did within the debate over supplying tanks. Britain’s choice final month to ship Ukraine 14 Challenger 2 battle tanks, in addition to artillery and ammunition, helped prod a reluctant Germany and the US to ship battle tanks of their very own.

Mr. Zelensky, whose go to was introduced by Downing Road barely two hours earlier than his Royal Air Power airplane landed, arrived in London with a full agenda. He needed to thank British leaders, previous and current, for being among the many first to ship weapons. After which he needed to current his purchasing record.

“London has stood with Kyiv from Day 1,” Mr. Zelensky mentioned to thunderous applause from lawmakers standing in Westminster Corridor. “I will likely be leaving at this time thanking you for highly effective English planes,” he added to scattered laughter.

In a dramatic gesture that doubled as a gross sales pitch, Mr. Zelensky offered the speaker of the Home of Commons, Lindsay Hoyle, with the helmet that the president mentioned belonged to one of many ace fighter pilots in Ukraine’s air power. A message was scrawled on it: “We have now freedom; give us wings to guard it.”

Whereas there are important qualms contained in the British authorities about sending fight jets, there are additionally vital reservoirs of help. Mr. Johnson, who visited Kyiv a number of instances and cultivated a friendship with Mr. Zelensky, renewed his name for Britain and different Western allies to grant Ukraine’s request.

“Your highly effective and passionate attraction have to be heard,” Mr. Johnson wrote on Twitter after attending Mr. Zelensky’s speech. “There’s nothing to be misplaced and all the things to be gained by sending planes now.”

Mr. Zelensky returned the heat. Throughout the speech, he singled out Mr. Johnson, saying, “Boris, you bought others to behave.”

At a number of key moments earlier than and throughout the almost yearlong conflict, Britain has thrust itself into the vanguard of Western navy help for Ukraine. Early within the battle, Mr. Zelensky mentioned, shipments of British antitank missiles enabled Ukrainian troops to halt the advance of the Russian Military.

Britain has skilled 10,000 Ukrainian troops, together with troopers who arrived final week to learn to function the Challenger tanks. Along with pilots, Britain mentioned it could start to coach Ukrainian marines.

In his information convention with Mr. Zelensky, Mr. Sunak mentioned their talks centered on extra short-term fight wants like tanks and long-range missiles. He took credit score for Britain’s choice to supply tanks, saying it had goaded others to behave.

The 2 leaders are an odd pair: Mr. Zelensky is a charismatic former actor and comic, Mr. Sunak a button-down former funding banker. However Mr. Sunak has maintained the staunch help for Ukraine that started below Mr. Johnson.

Britain’s hawkish response displays each its vexed historical past with Russia, which it blamed for poisoning a Russian agent on British soil, in addition to a self-conscious effort by Mr. Johnson to drape himself within the mantle of his hero, Winston Churchill.

However the conflict has additionally compelled Britain to confront its cozy, typically corrupt, ties with Russian oligarchs, lots of whom have used London to shelter and launder their property. Britain has blacklisted dozens of oligarchs, although critics say it has not achieved almost sufficient.

On Wednesday, the British authorities introduced a raft of recent sanctions concentrating on the Russian navy and loyalists of President Vladimir V. Putin, with the goal of “undermining his conflict machine to assist Ukraine prevail,” the British international secretary, James Cleverly, mentioned in an announcement.

The record contains a number of corporations that help Russian navy operations, together with CST, a drone producer, in addition to companies that offer navy elements and software program concerned in navy aviation. 5 people had been additionally focused for his or her obvious ties to Mr. Putin’s residences.

Mr. Zelensky’s emotional handle adopted the weekly ritual of Prime Minister’s Questions, a usually rough-and-tumble session through which Mr. Sunak and the opposition chief, Keir Starmer, go toe to toe. Fairly than a partisan cage match, nonetheless, this session was largely a show of unity in help of Ukraine.

Demonstrating that bipartisanship, Mr. Starmer inspired the federal government to proceed its navy help, referred to as for Mr. Putin to be prosecuted for conflict crimes in The Hague and proposed that the British authorities use frozen Russian property as funds to reconstruct Ukraine after the conflict.

In talking in Westminster Corridor, Mr. Zelensky joined an especially choose group of international dignitaries, together with President Barack Obama and Nelson Mandela, the previous South African chief.

The corridor, within the shadow of Large Ben, is without doubt one of the most hallowed locations in British public life. Erected by King William II in 1097, it’s the place King Richard I had his coronation banquet in 1189 and Thomas Extra was tried for treason in 1535. It was final used for the lying-in-state of Queen Elizabeth II after her dying in September.

Reporting was contributed by Aurelien Breeden in Paris, Megan Specia in London and Stephen Fortress in Lulworth Camp, Dorset, England