Callistemon, in regard to your post @19:39 today, it has to be remembered that the Parliamentary Labour Party was born out of the trade union movement over one hundred years ago when it was realised by those unions that such things as better education, health and housing for its members could not be gained by way of shop floor influence.
After the initial setup of the Parliamentary Labour Party, its administration and policy making was left to the Constituency Labour Parties with its finance being largely paid for by the affiliation subscriptions made by the trade union members. That situation happily continued for very many years with the trades unions and Labour party acting in support of each other in times of requirement.
However, during the Blair era that long-lasting alliance very much changed. Blair never once attended any trade union or TUC conferences and largely totally ignored the Broader Labour Movement while at the same time allowing the introduction of zero-hours employment contracts and Gig Economy working conditions. In that, Blair still continued to accept the affiliation subscription of those often low paid trade union members.
In 2010 following the banking crisis and Labours defeat in the 2010 General Election, the Broader Labour movement began to take action to gain a greater say in policymaking and within seats held on structural positions within the Parliamentary party. Out of that demand, the affiliated members in the broader Labour movement were allowed for the first time a vote in the election of the Labour Party Leader and that combined with a huge rise in direct Labour party membership, which was largely affiliated trade union members joining the Labour party directly, brought about Jeremy Corbyn as leader of the Parliamentary party.
The above is why I believe that Broader Labour Movement (in reality the trade unions) will never once again accept a situation where their members pay the bills of the Parliamentary Labour party without having a large say in policymaking and holding a substantial number of seats on its National Executive and within the constituency parties.
For what its worth, I feel that the trades unions should withdraw support from the parliamentary Labour party, for those unions have achieved huge success through the courts in regard to such matters as Gig Economy working in recent months, which has led to a rise in trade union membership in several industrial sectors without any assistance from the Labour party whatsoever.
Therefore the time may well be right for a complete realignment of left wing politics in Britain with the Broader Labour Movement launching a fresh political wing.
If the existing Labour Party can survive without the support of the wider movement, so be it, as that would set it free to have whatever policies and leader(s) it wished.