Alan Thornett, the historic leader of the Mandelist Fourth International in Britain (which currently carries the name Socialist Resistance), has published a longer article in which he calls for a YES to Britain’s membership in the EU. This document is a paragon of opportunism.
All the other groups with which we have dealt in this essay try to put forward principled arguments and theoretical considerations to defend their position. While we do not agree with any of them, one cannot deny that they desire to present fundamental arguments. In contrast to them all, Alan Thornett and Socialist Resistance (SR) apparently feel free from catering to principles, for Thornett does not even pretend to put forward any such arguments when developing his position. Instead, he entirely and exclusively deduces his position from what he assesses is the dominant opinion of those sectors of the left which are relevant for his group’s current political maneuvers. This is chvostim par excellence, tailing behind the mood prevalent among the petty-bourgeois left. Based on this opportunist method, Thornett and SR can justify why they supported the campaign for Britain to exit in 1975, but are not able to justify why they are for the opposite position today.
“With previous struggles around the EU—the introduction of the Maastricht Treaty and the single currency in the 1990s for example—it was possible to be part of broad left wing No campaign that was based, at least to some extent, on socialist and working class principles and represented something significant.” 
Today however, the left is less enthusiastic on Britain’s exit from the EU. Hence Thornett and SR are free to change their positions:
“The left in Britain (in its broadest sense) is more pro-EU today than at any time since Britain joined the project. This has been due, at least in part, to the fact that politics here in Britain have shifted to the right to the extent that some aspects of EU policy are progressive in relation to it. (…) What is more surprising, however, given the current role of the Troika in Greece, is that the trend on the radical left has been the same. It is harder today, amongst the radical left, to argue that the EU is a bosses club than it has ever been. And even where this is accepted, as in Left Unity for example, there is probably a majority against exit under any circumstance—leaving the current referendum aside. (…) We can say with confidence when it comes to the referendum campaign itself that it will reach new heights (or plumb new depths) in terms of xenophobia, nationalism and racism. It will be a carnival of reaction. (…) The main No campaign will be totally dominated by UKIP and the Tory right wing. This poses something of a dilemma for those on the left (like ourselves) who see the EU as a reactionary institution designed to ensure that the national governments impose the austerity agenda and increase the rate of exploitation more effectively but have no wish to be associated with the right in any form it might take. SR has not yet taken a view on this. In my opinion, however, the right way to vote in this referendum will be Yes.”
En passant we note that in fact it is not in fact “the left” which has become pro-EU. As we have shown above, the largest organizations – the CPB, the SPEW, and the SWP – are for a NO-vote. However what is true is that those sectors of the left to which SR is currently opportunistically adapting – the SSP in Scotland and Left Unity in England and Wales – are for a YES-vote. Hence, Thornett and SR have to adapt to this milieu and change their position from NO to YES regarding Britain’s membership in the EU.
At least, we should thank Thornett for being open and honest about the Mandelites’ method of opportunism. In contrast to others, at least he does not hide his adaption to the petty-bourgeois progressive milieu behind orthodox Marxist phrases.
 Alan Thornett: On the European Union referendum in Britain: We need an internationalist, not a nationalist opposition to the EU, Socialist Resistance, 18 June 2015, http://www.europe-solidaire.org/spip.php?article35191