A British businessman found dead in China was killed with cyanide, it has been reported.

Neil Heywood was murdered on the orders of a fallen Communist Party chief, according to the Mail on Sunday.

The newspaper quoted "respected Mandarin-language websites" saying Mr Heywood, 41, died from cyanide poisoning after allegedly having an affair with lawyer Gu Kailai, wife of Bo Xilai, seen until recently as a future leader of China.

Mr Heywood was found dead on November 15 in Chongqing, in central China. Britain asked China to investigate his death and it emerged last week that Mrs Gu was being probed for "intentional homicide".

The Mail on Sunday said it was alleged that Mr Heywood was murdered after helping Mrs Gu to siphon nearly £800 million of assets overseas.

A city official has allegedly confessed that he prepared the poison and handed it to an employee of Mr Bo, who administered it to Mr Heywood on the party chief's instructions. Mr Heywood was a friend of the family of Mr Bo, a former rising star in Chinese politics who served as local party chief in Chongqing.

At the time, Chinese officials said the British expat died of "excessive alcohol consumption". But friends questioned this, saying the businessman was not a heavy drinker.

In February, Mr Bo's former police chief Wang Lijun sought refuge in the US consulate in China. It is thought he made a number of claims against the politician and Mrs Gu, including her alleged role in Mr Heywood's death.

State media reported on Tuesday that Mrs Gu and Zhang Xiaojun, an orderly at Mr Bo's home, had been arrested. Meanwhile, Mr Bo has been suspended from the Communist Party's 25-member Politburo amid allegations of "serious discipline violations".

A Foreign Office (FCO) spokeswoman said: "We are aware of the latest media reports. As there is an ongoing Chinese police investigation into this case it wouldn't be appropriate to comment further. We remain in close touch with the Chinese authorities and Mr Heywood's family."