There are no guarantees, but a successful struggle against capitalism entails many allies and tactics. The Britsh trades unions failed to support the action: indeed, at their conference, they condemned it. Their unconditional loyalty to the false regime of the Labour party has lost the day.
The fuel tax protest was neither a Seattle type event, nor a classic workers strike, but it collapsed because the socialist parties, the autonomous left and the trades unions failed to give a progressive lead; they could have taken strike action if not in direct support, at least in parallel. The protest was confused, but indications suggest black / white solidarity, the explusion of right wing elements from the picket lines, and opposition to the oil companies policies. Not bad at all.
As a group of small entrepreneurs, caught between the ruling and the working class, they might have appreciated the support of the proletariat. the unions would have gained a lot of goodwill (as well as concessions for their own demands from the government), but now the farmer will be convinced that the town dweller neither cares nor understands his problems. In addition, the unions are locked still further into Blair's christian poulist regime.
Already, Home Office Director Jack Straw is draughting new authoritarian contigency measures in consultation with the the oil companies (not the protesters, note), and the police, measures which can also be used against the unions too. Perhaps they intend to split the oil profits between the three of them ?