David Cameron is holding talks with a top Chinese Communist official, where he is "likely" to raise the death of British businessman Neil Heywood.
Li Changchun, a member of the all-powerful Politburo Standing Committee, is visiting Downing Street for talks on trade and Britain's links with China but they are also expected to discuss the case.
Mr Heywood's death has caused a political scandal in China, and sparked rumours of a rift in the country's top leadership.
New reports claim the British business consultant was poisoned after threatening to expose the financial dealings of the wife of a top Communist Party leader.
Mr Heywood - who lived in China for more than a decade - died in a hotel room in the southern city of Chongqing in November.
Chinese police originally said the cause of the British ex-pat's death was alcohol poisoning, but then quickly cremated his body without performing an autopsy.
The British Government asked the Chinese to re-investigate the matter early this year after hearing of "suspicions and rumours surrounding his death".
Foreign Secretary William Hague said Britain wants to see "the conclusion of a full investigation that observes due process, is free from political interference, exposes the truth behind this tragic case, and ensures that justice is done".
In a written statement to the Commons, he said allegations about Mr Heywood's death were made by former Chongqing police chief Wang Lijun to US consular officials on February 6.
Mr Hague was told the next day and immediately ordering diplomats to urge the Chinese authorities to investigate.
A formal request for an investigation was made on March 22 and the British Ambassador was told on April 10 that one had been launched, the Foreign Secretary said.
Days later, China's state media announced that Mr Heywood had been murdered and the chief suspect was named as Gu Kailai , the wife of the Communist Party Secretary of Chongqing, Bo Xilai.
Mr Bo, who was in the running to join the all-powerful Standing Committee of the Politburo later this year, has been sacked and is also under investigation.
State media say Ms Gu and Zhang Xiaojun, an orderly at Mr Bo's home, have both been arrested.
The affair is the biggest political scandal to rock China in decades but because Mr Heywood was known to be friends with Mr Bo and his family, many have wondered about a motive for the alleged murder.
New reports from the Reuters news agency quote sources close to the police investigation who claim that Mr Heywood helped Ms Gu move large sums of money overseas.
It is alleged the Briton asked for a bigger cut of the transactions, angering Ms Gu, and that he then threatened to expose their financial dealings .
The clear implication is that the money being transferred was ill-gotten.
Mr Bo is thought to have earned an official salary of around £300 pounds a month, while he once described Ms Gu to reporters as a "housewife".
The family has long been dogged by allegations of corruption, which led Mr Bo to publicly complain that people were "pouring filth" over him and his wife.
The Reuters report also quotes sources close to the police investigations as saying that Mr Heywood was killed by a drink laced with poison.
Asked whether Mr Cameron planned to raise the Heywood case with Mr Li, a Downing Street spokeswoman said: "It is likely to come up. I think he will echo what the Foreign Secretary has said, that we welcome the investigation that is ongoing and we look forward to seeing the outcome of that."