The Malaysian high court has rejected an appeal for release from prison by the adopted brother of the ousted deputy prime minister, Anwar Ibrahim.

The man, Sukma Dermawan, was jailed for six months after admitting homosexual acts with Mr Anwar.

But he says in his appeal that, as a Muslim, the charges against him should have been tried under Sharia law by an Islamic court.

Mr Anwar's former speech writer, who was jailed with Mr Sukma in September, lost an appeal last month in which he alleged that his confession to similar offences had been obtained through ill-treatment.Mr Anwar is himself on trial for illegal sex and corruption, but says the charges have been fabricated as part of a political conspiracy.