London, Aug 11 - British Prime Minister Gordon Brown said he is angered by the sentence of 18 months' house arrest passed against Myanmar opposition leader and Nobel laureate Aung San Suu Kyi by the country's military rulers Tuesday.

Brown said he was 'saddened and angry' by the conviction.

He said the sentence was 'further proof that the military regime in Myanmar is determined to act with total disregard for accepted standards of the rule of law and in defiance of international opinion.

'This is a purely political sentence designed to prevent her from taking part in the regime's planned elections next year,' Brown said.

He said as long as the opposition leader and other detained opponents were prevented from taking part in the political process, the elections 'will have no credibility or legitimacy'.

'The facade of her prosecution is made more monstrous because its real objective is to sever her bond with the people for whom she is a beacon of hope and resistance.'

Irene Khan, the head of human rights group Amnesty International, said the military regime's act of reducing a jail sentence to house arrest must not be seen as a gesture of leniency.