China promises 'thorough' investigation into Neil Heywood's death

China's ruling Communist Party said today that it is committed to probing a political scandal that includes an investigation into the suspected murder of a British businessman, following new appeals from Britain's senior politicians for a swift investigation that is free from political meddling.

The statement by the official Xinhua News Agency came hours after Prime Minister David Cameron and Foreign Secretary William Hague both held talks with China's propaganda chief, Li Changchun, during his visit to Britain.

They demanded assurances over inquiries into the November 15 death of Briton Neil Heywood in a hotel in the south western Chinese city of Chongqing that has been linked to the wife of the metropolis' former top official, Bo Xilai.

The appeals are a sign of the extraordinary international links to the dismissal of Mr Bo, who had been among China's most powerful politicians.

The political crisis is China's biggest - and by far messiest - in years.

The scandal was set in motion on February 6, when Mr Bo's former right-hand man, Chongqing ex-police chief Wang Lijun, made a surprising visit to the US consulate in the nearby city of Chengdu.

Mr Wang expressed suspicions about Heywood's death, originally termed accidental, before being taken into the custody of investigators in Beijing. Mr Wang's whereabouts are now unknown.

The party's Central Committee "has made a resolute decision to thoroughly investigate related events and release information in a timely manner, a manifestation of its high sense of responsibility to the causes of the party and the people," the Xinhua statement said.

"Based on the facts made public so far, the Wang Lijun incident is a serious political event that has created an adverse influence both at home and abroad, the death of Neil Heywood is a serious criminal case involving the kin and aides of a party and state leader, and Bo has seriously violated party discipline," the statement said.

Mr Bo was sacked as Chongqing's party secretary on March 15 and suspended as a Politburo member for what were described as serious violations of discipline, possibly including interference in a police investigation or corruption.

Mr Bo's wife, Gu Kailai, and aide Zhang Xiaojun were formally named on April 10 as suspects in the death of Heywood, a long-time resident of China and a friend and business associate of the Bo family. They have been handed over to investigators.

Speculation has focused on the possibility that Mr Heywood was poisoned, rather than dying from excess drinking or a heart attack as was originally claimed.

The scandal has been hugely embarrassing for the country's insular leadership, both in its salacious revelations and in the involvement of foreign political forces. With the proliferation of the internet and microblogging, the leadership has struggled to control the spread of rumours and unconfirmed reports about the involvement of other top leaders.

Mr Bo had been considered a candidate for the party's all-powerful Politburo Standing Committee when new members are picked this autumn, although his political career now seems over.

That has raised new questions about the makeup of the future leadership, although Vice President Xi Jinping remains in place to take over as party leader in the autumn and president next spring.