A British investigator and his American wife who were hired by UK drugs giant GlaxoSmithKline have been jailed after being found guilty of illegally obtaining and selling private information.

Peter Humphrey, 58, was sentenced to two and a half years while Yingzeng Yu, 61, received a two-year term following a one-day trial in Shanghai today.

They were accused of obtaining information on Chinese citizens by illegally buying it from others, as well as with hidden cameras, or by following people.

Prosecutors said the couple, who ran the Shanghai-based corporate intelligence and consulting firm ChinaWhys, compiled information for reports to clients that were mainly multinational companies such as GSK.

The couple have 10 days to appeal.

A Foreign Office spokeswoman said: "We note the verdict in this case.

"We have continually called for a transparent process leading to a swift and fair conclusion to this case, in accordance with Chinese law.

"It would be wrong to comment further while the case remains open to appeal."

The couple were arrested last August and worked under contract for GSK, which is accused in a separate case of bribing Chinese doctors and hospitals to use its products.

Their arrest coincided with an investigation of GSK but authorities have not indicated whether the two cases are linked.

A spokesman for GSK said the pharmaceutical company would not comment on the case.

The couple's son, Harvey Humphrey, 19, who was allowed to watch the trial from the public gallery, told reporters afterwards: "Very sad about the court's verdict, but I hope that the authorities will take into account their poor health condition."

Earlier the teenager accused the multinational of "misleading" his parents and claimed the company had "gone into full survival mode", which he said included denying any connection with his parents.

He told Sky News: "This whole thing stems from GSK's misleading of my parents and I think in that process they trod on several powerful toes, if I may put it that way.

"I am not particularly critical of the Chinese in this, I know it's frustrating, it's been very confusing and lots of the time it may seem like injustice but we have to really go back to what caused this, the root of the problem, and the root of the problem really from where I'm sitting is the way GSK behaved in this matter - and as a matter of fact, they have not improved at all since this started."

Mr Humphrey said there was a chance at the beginning to cooperate to find out what had happened, adding: "But (GSK) did not extend any helping hand and they've gone into full survival mode, denying all connection with my parents.

"But also I feel that possibly they didn't even know how to solve their own problem. I think there's a bit of naivety with them as well."

He said they had already been in prison for almost 14 months and had looked in "mediocre" health.