The intriguing case of Nguyen Ha Phan - the only person ever dumped from Vietnam's ruling Politburo - is now unlikely ever to go to court, political sources said. Mr Phan, accused of treason, remains in closely monitored obscurity in the south after being stripped of his Communist Party membership in the shock dumping 18 months ago. Officials insist he is not under house arrest but his movements are understood to be restricted. The loss of his party card - effectively the highest possible internal punishment - means he cannot participate in any political activity. Mr Phan, 67, was ejected just weeks before the party's congress last year, when evidence was produced against him in a closed-door meeting of the party central committee. Members were told of Mr Phan's loyalty to former French colonialists and possible collaboration with South Vietnamese secret police during the war. The key allegations concerned Mr Phan's detention by US-backed South Vietnamese from 1959 to 1963, when he gained his release by supplying names of fellow southern revolutionaries, some of whom were later killed. The claims stunned the party, whose members face gruelling family, ideological and background checks before even the smallest promotion is considered. Few details ever appeared in Vietnam's state press, nor was there a formal trial. 'Mr Nguyen Ha Phan is punished by the discipline of party excommunication for having made serious mistakes or wrongdoings in the past,' a Foreign Ministry spokesman said this week without elaboration. Mr Phan's dumping followed an extensive investigation involving both military and party investigative bodies.