Thailand’s jailed former Prime Minister Thaksin Shinawatra has been allowed to remain in hospital for medical treatment, the corrections department said on Thursday, citing the need to continue to closely monitor his health. The billionaire figurehead of the ruling Pheu Thai Party has been in hospital since his return in August from 15 years of self-imposed exile, after complaining of chest tightness and high blood pressure within hours of arriving at a Bangkok jail to serve eight years for abuse of power.