This is what he has to say on the matter:
Thirdly is the question of the Labour party. For anyone concerned with socialist strategy and working class politics, how one deals with Labour remains *the* central strategic issue. Though I have blown hot and cold over the characterisation of Labour since being a SP member, but I never believed the party's settled position that it was a straight party of capital not fundamentally different from the Tories and LibDems. Aside from the formal affiliation of most of the major trade unions, there remain thousands of small scale links. For instance the majority of union activists who are members of a political party are in Labour. You'll find thousands of Labour party members in community-based campaigns too. Neither can you hide from the fact that despite some decomposition in Labour's support, its working class base remains stubbornly welded to it.
Like it or not (as the case is perhaps most likely to be) any working class political project which does not involve Labour may as well not exist, and any nationwide programme for workers' representation in Parliament begins and ends with Labour.
It is also true that the Labour Party, for all its sins (and recently they have been many) is a special kind of party: not only is it distinct by its very nature from the Bourgeois parties but it's structure and relationship with the labour movement as a whole makes it unique amongst the social-democratic parties of the Second International in Europe.
It is for these reasons and others that Phil BC should not be asked to justify his decision to join Labour, but those of us who deem themselves committed socialists and serious labour movement activists yet choose to remain outside of the Labour Party who should think carefully about our justifications.
I, as someone who has himself considered a similar move in the recent past, and drawing inspiration from Harry Pollitt and his “Why You Should Be A Communist” (1945) pamphlet have come to the conclusion that a Communist Party organising independently of the Labour Party (and also standing clearly apart from the ultra-leftism so prominent in the extra-Labour left) plays a vital role within the Labour movement, even if its destiny is not Parliamentary success or the glamour of Government. Much as a minor species can play a vital role within an eco-system, in which its demise could slay elephants, the absence of a Party which can put forward clearly and agitate for a programme of true working class politics, a party which can train, educate and indirectly influence young trade unionists and socialists, a generation of Labour Party activists can spring up who have little direct experience of genuine socialist politics, perhaps sensing the hollowness of the New Labour programme but not knowing the alternative.
This may seem an unrealistically grandiose view of the Communist Party, and I am by no means suggesting that the current CPB is capable of taking on this role, but many of the best and most prominent activists within the Labour Party and the Trade Union movement were fellow travellers if not outright former card holders.
It is in rebuilding a party which can take up this duty as its own, in a symbiotic (if not friendly) relationship with the Labour Party, which I feel I can play a role, and in which I feel I can do more good than I can as a fringe activist within the Labour Party.