Well, it sure added some serious percentage to the leave
Do you wonder why there even was a referendum?
Compare 1997: Sir Jammy Fishpaste hates Europe, spends millions of his own money promoting his Referendum Party, gets nowhere. Because it's "cool Britannia" and the common man is doing well for himself. People think he's a nutter and all he achieves is keeping 4-11 Tories out of power by sapping their votes
But the 2008 crash wrecks the country. UKIP builds a voter base over years, and gets an enormous share of the vote. That's a warning shot for the Tories, whose voters UKIP are sapping. They only just squeaked through a hung parliament with a Libdem coalition. Hence Gambling Dave offers a referendum to bring Europe haters back to his party so he can remain in power.
Those percentage points were already in place before Russia even got going.
Farage was basically a Putin asset, for years; I don't doubt that a lot of the sentiment was there before any influence, but to my recollection the influence was obvious and very heavy
He added in the Commons "I haven't at any point said it altered the result." https://x.com/SkyNews/status/2109670197833429270
The head of MI5 backed both these statements, stressing both that Russia did interfere and didn't have much of an effect: "There is a really important difference between interference attempted and outcome swayed" https://www.theguardian.com/politics/2026/oct/13/russia-brex...
Farage is a lot of things, but I wouldn't claim he was a Putin asset as we don't have evidence of that. The evidence we do have against him (dodgy foreign money pouring into his bank account, him springing into action for his paymasters, him having criminal fraudsters on staff, etc.) is just as damning. You have to be careful in making such claims. Arron Banks (the main source of money for Leave.EU) had dealings with the Russian state around the time of his Brexit campaign, and was being investigated for these dealings. But, ultimately nothing untoward was found, and he sued Carole Cadwalladr who merely hinted that he had Russian financial ties. She is now bankrupted by having to pay his enormous legal costs. https://en.wikipedia.org/wiki/Carole_Cadwalladr#Banks_v_Cadw...
Worth remembering... Anti-globalization and anti-liberalization were slogans and policies of the socialist left in the late 90s and 2000s. Battle of Seattle, Occupy, etc. Voices marginalized and mocked by the neo-liberal centrist "left" (not left) in the Democratic party, Labour party, mainstream European govt's, Canadian Liberal party, etc. Manufacturing jobs were dumped overseas, union membership declined, middle class incomes plummeted, 2008 drained people's financial well being, while housing prices skyrocketed etc. And same "moderate" forces also went to war in the middle east, etc. etc.
Obama ran on left populist slogans but actually governed from the neo-liberal centrist right.
Actual socialist left voices and formerly moderate social democratic policies generally had no voice or power in government anywhere, Corbyn was run out of the room, Bernie isolated, etc.
So it's no surprise that the right and far right saw the vacancy and exploited it. The rise of Trump, of UK Reform, etc. ties directly into this sense of hopelessness and anger people had.
Now the "conservative" right -- which was formerly pushing liberalization the strongest -- talks in angry tones about "globalism" instead of "globalization", and it's caught up with anti-Semitic dog whistles, national chauvinism, etc. etc. That shit sells.