Media playback is unsupported on your device Media caption John Sudworth reports from Shanghai: ''Peter Humphrey has already been paraded on state TV confessing his guilt''

A British investigator and his wife are being tried in China for illegally trafficking personal data.

Peter Humphrey and his American wife Yu Yingzeng were arrested in August 2013.

They are accused of illegally obtaining Chinese citizens' personal information and selling it to China-based multinational corporations, including GlaxoSmithKline (GSK) China.

GSK China, which is being investigated for possible bribery, hired Mr Humphrey last year.

The trial is taking place at the Number One Intermediate Court in Shanghai. Information about proceedings is being released on its official microblog.

Prosecutors said the couple had illegally obtained more than 200 pieces of information, including phone records and household registration data, on individuals which they resold to clients.

"Generally speaking... I don't dispute (the prosecutor's indictment)," the official microblog quoted Mr Humphrey as telling the court.

According to the transcript, he told the court the services his company supplied were aimed at "reducing risks, especially risks in regard to fraud and corruption".

"We would ask other consulting companies to help us and they could help us obtain the personal information of Chinese citizens," he reportedly told the court.

Image copyright AFP Image caption The court released an image of proceedings showing Mr Humphrey (2L) and Yu Yingzeng (in red)

Image copyright AFP Image caption The trial is taking place at the Shanghai Intermediate Court

GSK probe

Chinese authorities have not made an explicit link between this case and the GSK probe.

The arrest of Mr Humphrey and his wife came weeks after he delivered an investigation report to GSK.

Early in 2013 an email was sent to GSK's London-based CEO Andrew Witty accusing GSK China's general manager Mark Reilly of being behind systematic corruption in the company's China operation.

A sex tape featuring Mr Reilly and his girlfriend was later also sent.

Mr Humphrey's corporate investigations company, ChinaWhys, was asked to find out who had sent the email and how the video had been filmed.

GSK suspected a former senior staff member, said to have top-level political connections, who has denied being the whistleblower.

In June, ChinaWhys delivered its report. Chinese authorities shortly afterwards opened a bribery investigation into GSK and then arrested Mr Humphrey and his wife.

John Sudworth, BBC News, at the court in Shanghai

The court microblog feed gives the appearance of openness but it is, like the trial itself, under the strict control of the Communist Party. Much of the more intriguing aspects of the case will remain hidden.

For example, what about GSK's former manager, Vivian Shi, reported to have family connections to the top echelons of power? It was Ms Shi that GSK had asked Mr Humphrey to investigate, believing her to have been orchestrating a smear campaign against the company. She's denied being the whistle-blower but the court case is unlikely to make us any the wiser, either way.

For the foreign business community the case is probably best simply seen as a reminder of the lack of independent judicial recourse when things go badly wrong, as well as a worrying sign that China may be tightening its scrutiny of corporate investigation firms - so crucial for anyone wanting to navigate this country's murky business environment.

GSK China remains embroiled in controversy over alleged systematic bribery of doctors.

Mr Reilly is currently being investigated by Chinese authorities, as are at least two other senior GSK China executives.

He is alleged to have pressed his sales team to bribe doctors, hospital officials and health institutions to increase sales of GSK products.

He is currently effectively detained in China and has made no recent comment.

GSK has described the allegations as "deeply concerning", saying it is "learning lessons from this situation" and is "determined to take all actions necessary as a result".

How case unfolded: