UK diplomats have been given permission to attend the trial of an ousted Chinese politician's wife on a charge of murdering British businessman Neil Heywood, it has been disclosed.

The Foreign Office said British officials will attend the trial of Gu Kailai, which begins on August 9 in the eastern city of Hefei.

It is considered unusual for foreign observers to be granted access to such politically sensitive court cases in China.

"We can confirm that British diplomats will attend the trial," said the Foreign Office, with a spokesman adding: "The details of the ongoing investigation are a matter for the Chinese authorities.

"However we are glad to see that the Chinese authorities are continuing with the investigation into the death of Neil Heywood. We are dedicated to seeking justice for him and his family and we will be following developments closely."

Mrs Gu is the wife of Bo Xilai, the former Communist Party chief in the city of Chongqing who was once considered a strong contender for membership of the nine-member Politburo Standing Committee and possible future leader of the country.

He was sacked from his position in March after allegations surfaced linking Gu to Mr Heywood's death, and he remains under investigation by the party over corruption claims.

Mrs Gu and family aide Zhang Xiaojun are accused of poisoning Mr Heywood, a long-time associate of Bo's family. His death in a Chongqing hotel last November was initially ruled accidental, and put down to alcohol abuse, though friends said that Mr Heywood was not a big drinker.

But murder suspicions came to the fore after a former Chongqing police chief visited a US consulate in China and divulged information allegedly linking Gu to Mr Heywood's death.

The case has convulsed China's political world ahead of the expected handover of power to a younger generation of leaders at the Communist Party's five-yearly National Congress in Beijing this autumn.