A significant factor in the long-term failure of the Miners Strike was Arthur Scargill's decision not to ballot NUM members on whether to go to a strike, which resulted in Scargill issuing the decision to strike by diktat, which was a massive PR coup for the right-wing tabloid press. The reactionary media were therefore able to present the NUM as anti-democratic, dividing the miners themselves and their supporters in the general community, and providing the pretext for the creation of the rival Union of Democratic Miners - which was exposed, many years later, as having been MI5 funded. It's also rumoured the NUM activist who advised Scargill to proceed to a strike without a ballot was an MI5 plant!

In contrast the Anti-Poll-Tax campaign succeeded because it defended democracy, as Margaret Thatcher's planned Poll-Tax was designed to link the right to vote and the electoral register to what's now referred to as Council Tax payments - what the Tories planned was that those too poor to be able to afford this taxation would try to avoid payment by not registering to vote.

The success of the Anti-Poll-Tax movement is often debated in terms of the impact of the Poll Tax Riot, therefore debated in terms of the morality and effectiveness of radical violence, but the truth is that both the Miners Strike and Poll Tax Riot involved violence, but one failed, and the other succeeded. Violence was not the deciding factor. What caused the NUM to fail was that their campaign was perceived to be anti-democratic, and what caused the Anti-Poll-Tax campaign to succeed was that it defended democracy (and this is all the more ironic given that some of hard-left groups who fought against the Poll Tax were in fact ideologically opposed to the Parliamentary democracy that, bizarrely, they ended-up successfully defending).

Similarly the current Anti-Cuts movement will succeed if it defends true democratic principles, but FAIL if it is perceived to be opposing democracy; and, likewise, the Anti-Cuts movement will succeed if it exposes thieving, expenses-fiddling, corrupt, anti-democratic, war-mongering politicians as the real extremists, but will fail if they are able to smear us as extremists, particularly by association with ANY form of terrorism...

 https://www.indymedia.org.uk/en/2011/09/485095.html