Yes – The Fabian Society is treasonous and its members should be banned from holding public office in the UK.  Fabians´ ultimate aim is One World Government, which makes it opposed to the parliamentary democracy and constitutional monarchy that are corner stones of the British way of life.

The Fabian Society was formed in 1884 with a Marxist agenda, but did not call for revolution. Rather it chose stealth and a wolf in sheep´s clothing as its emblem.  It was no coincidence that George Orwell´s famous book against totalitarianism was called 1984.  He thought that it would take a 100 years for the aims of the Fabian Society to become a reality.

George Orwell (penname of Eric Blair) was never a member of the Fabian Society (led by Sidney and Beatrice Webb with adherents like George Bernard Shaw) which he said was comprised of blow-hard intellectuals, pretending to be Socialists,  when deep down they were Communists lusting for power and control. Thanks to OrwellToday for this and more.

The Fabian Society is with placemen in powerful places in The UK, in parliament, the judiciary and Education.  So it is quite possible for a case about government overreaching itself to be heard by a judge, who is a Fabian with an interest in the case.

To make it worse, the best and brightest are not Fabians , rather it is the ambitious who become members and get promoted beyond their level of competence.

It would be an infringement of Freedom of Association to ban The Fabian Society.  But the government could pass a law preventing people holding public office, if they are members of a club/society, whose aims were incompatible with Britain way of life.