In the UK, several Labour politicians have been embarrassed by phone footage of speeches given to groups of far left activists. For example, the shadow chancellor was recently revealed as celebrating the Great Recession in 2008 as something that he had been waiting years for in his fight to overthrow capitalism. And phone footage of Momentum meetings has shown activists scheming to have moderate politicians deselected (essentially removed from office for those not familiar with UK politics). There has definitely been a backlash in the polls against these revelations.
None of which is true.
It's all true.
The Momentum footage appeared on a Channel 4 Dispatches documentary. I've viewed it myself. Similar evidence was shown on a BBC1 Panorama report. Again, I've viewed it myself. The footage of the shadow chancellor was highlighted by the Daily Telegraph and it's also on YouTube. Once more, I've viewed it myself.
Your denial of reality demonstrates why video evidence is so important if the public is to know the truth.