China has fined GlaxoSmithKline (GSK) a record three billion yuan ($489 million) for paying bribes to doctors to use its drugs, underlining the risks of doing business in the country while also ending a damaging chapter for the British drugmaker.

A court in the southern city of Changsha handed suspended jail sentences to former head of GSK in China Mark Reilly and four other executives of between two and four years, according to state news agency Xinhua.

Briton Reilly will be deported, a source said.

The verdict, handed out behind closed doors in a single-day trial, highlights how Chinese regulators are increasingly cracking down on corporate malpractice.

However, it also offers GSK a potential way forward in the fast-growing Chinese pharmaceutical market, a magnet for foreign firms who are attracted by a healthcare bill that McKinsey & Company estimates will hit $1 trillion by 2020.

'If GSK China can learn a profound lesson and carry out its business according to the rule of law, then it can once again win the trust of China's government and people,' Xinhua said.

The fine, equivalent to around four per cent of GSK's 2013 operating profits, was less than some investors had feared. GSK will take a charge in the third quarter and pay the penalty from existing cash resources.

GSK said it remained committed to China and promised to become a 'model for reform in China's healthcare industry'.

'GSK has reflected deeply and learned from its mistakes, has taken steps to comprehensively rectify the issues identified at the operations of GSKCI, and must work hard to regain the trust of the Chinese people,' GSK said in a written apology.

Future commitments include investment in Chinese science and improved access to medicines across the country through greater expansion of production and flexible pricing, it said.

Roche chief executive Severin Schwan said in an interview this week: 'I remain very bullish about China, even though currently the market has slowed down and pricing pressure has increased.'

GSK also faces investigations into its overseas practices by US and British authorities. Those investigations continue and could result in further penalties for the group.

'The SFO criminal investigation into the commercial practices of GSK and its subsidiaries continues,' a spokeswoman at Britain's Serious Fraud Office said.

In the US, GSK is being investigated under the Foreign Corrupt Practices Act, which prohibits bribery of public officials.

In addition to the high-profile Chinese case, GSK has been accused of corrupt practices, on a smaller scale, in Poland, Syria, Iraq, Jordan and Lebanon.

GSK said the activities by the firm's China unit were a 'clear breach' of GSK's governance and compliance procedures.

Chinese police first accused GSK of bribery in July last year when it said that the firm had funnelled up to 3bn yuan, exactly the same amount as the fine, to travel agencies to facilitate bribes to doctors and officials.

'Reaching a conclusion in the investigation of our Chinese business is important, but this has been a deeply disappointing matter for GSK. We have and will continue to learn from this,' chief executive Andrew Witty said.

The case is the biggest corruption scandal to hit a foreign company in China since the Rio Tinto affair in 2009, which resulted in four executives, including an Australian, being jailed for between seven and 14 years.

The judgment yesterday took many people by surprise, partly because Chinese authorities did not make the date of the trial public in advance.

The ruling from the Changsha Intermediate People's Court means China has charged GSK's China unit with bribery as well as the individual executives. Apart from Reilly, the other four '“ Zhang Guowei, Liang Hong, Zhao Hongyan and Huang Hong '“ are former company officials.-Reuters