I caused a little stir last year by suggested that the Brent Fightback group were essentially driven by the Loony Left and that their main goal was to attack the Labour Party.
I still think this is so, but it might be worth thinking about the idea more theoretically, using the concepts of the Austrian economist Joseph Schumpeter. Schumpeter suggested that political groups in a democracy behave rather as business men might be expected to. Whereas businessmen deal in money and what ever they are selling. Political groups are operating in a market for votes.
This makes sense of what many people consider a paradox. Groups such as Fightback, the Green Party and so on declare themselves to be left wing. The Labour Party is the UK's biggest left wing party and, I would argue, its only effective vehicle for progressive politics. Why are these like minded groups not allies?
The first explanation is not Schumpeterian. It is that the claims that such groups make are in fact untrue; that they do not really care about left wing objectives. I think that holds a lot of water. If you look at the reality, groups like Fightback seem much more interested in process than results. They enjoy going on demonstrations, the warm glow of condemning other people, and show little interest in the details of policy or the actual implementation of policies. That probably has a lot to do with the dynamics of fringe groups.
The Schumpeterian analysis is intellectually more interesting. Groups on the loony left have a range of slogans that are unlikely to appeal to Daily Mail readers or other people of a right wing persuasion. Whereas a broad church movement like the Labour Party has to appeal to at least a plurality of the UK electorate, the Far Left will never be able to get basically Tory voters to vote for them. Therefore they just ignore such people and are left in a field where the competition is among themselves and the Labour Party. Taking votes off the Labour Party is effectively their only way of gaining support. Hence they try various tactics such as claiming that there is no difference between Labour and Conservative. These can either be head on assaults, or attempts to undermine the Labour movement from within. People in the Labour Movement who attempt to do deals with the Far Left therefore perform the role that Lenin described as "useful idiots".
This leads to the further paradox that in many ways the extreme left actually benefit from having the most extreme right wing government in power imaginable. A really far right government attacks Labour from the Right while the loony left hack away from the other side, forcing Labour to fight on two fronts simultaneously. It is a situation rather similar to the Tarten Tories tactics of the SNP. The more obnoxious the London government is to Scots, the more the SNP can denounce it.
Whether any of this benefits either local government or democracy is highly questionable.