GlaxoSmithKline has confirmed that the Serious Fraud Office has begun a formal criminal investigation into the group’s commercial practices.
The world's first vaccine against malaria could be less than two years away after a successful trial.
GlaxoSmithKline has agreed to sell soft drinks brands Lucozade and Ribena to the Japanese firm Suntory for £1.35 billion.
The Serious Fraud Office has confirmed it has opened a criminal investigation into the commercial practices of GSK and its subsidiaries.
It appealed for whistelblowers from the company to help them with their inquiries.
Whistleblowers are valuable sources of information to the SFO in its cases.
We welcome approaches from anyone with inside information on all our cases including this one - we can be contacted through our secure and confidential reporting channel, which can be accessed via the SFO website.
The scandal is the latest in a number of corruption probes in Iraq, Poland and China against the company.
Anyone with any information can contact the Serious Fraud Office confidentially through their website.
Drugs giant GlaxoSmithKline said it intends to co-operate fully with the criminal investigation into its operations by the Serious Fraud Office. In a statement, the company said:
GSK is committed to operating its business to the highest ethical standards and will continue to co-operate fully with the SFO.
Pharmaceutical giant GlaxoSmithKline is under criminal investigation here in the UK, the company said.
The London-based multinational corporation said the Serious Fraud Office has opened a "formal criminal investigation".
The company is facing similar investigations in Iraq and China.
The UK-based drugs giant GlaxoSmithKline is facing fresh allegations of corruption after Chinese police accused senior executive Mark Reilly of bribery.
In a statement by the official Xinhua News Agency, police said GSK's Mark Reilly is accused of pressing sales teams to bribe doctors, hospital officials and health institutions.
It said that resulted in "illegal revenue" of billions of yuan - hundreds of millions of dollars.
British drugs giant GlaxoSmithKline is investigating allegations of corruption in Iraq, after claims emerged that it hired 16 state-employed doctors and pharmacists as sales representatives while they worked for the government.
The new allegations of corruption come just months after a major scandal in China, when 18 employees were detained on bribery charges.
Details of the new allegations were sent to the company earlier this year, the Wall Street Journal reports. In a statement, GlaxoSmithKline said:
"We are investigating allegations of improper conduct in our Iraq business. We have zero tolerance for unethical or illegal behaviour.
"In total, we employ fewer than 60 people in Iraq in our pharmaceuticals operation and these allegations relate to a small number of individuals in the country."
This is certainly a significant breakthrough. Doctors already have several weapons in their fight against Malaria, such as impregnated bed nets that stop the mosquitos biting you and spreading the parasite that causes malaria.
There are drugs that you can give if people do get malaria. You can spray to try to kill the mosquitos that spread it. But all those have problems and none are as good as a vaccine would be. That is a vaccine that attacks the parasite that causes malaria.
Dr Allan Pamba, from GlaxoSmithKline, talked about new doors that have opened in treatment:
GSK, the company that developed this one, spent half a billion pounds on it, and it has taken 30 years to develop. The trial is not finished yet, it has got about another year to run.
It could be approved by the European Medicines Agency next year and could be in use in Africa by 2015-16.
A new potential vaccine for malaria will only have an impact if it is made affordable to people in poor countries, Oxfam's health policy adviser Anna Marriott has warned.
She said previous cases show that companies can make drugs affordable to African governments, which can then provide treatments free of charge to poor people.
Marriott also stressed that the impact would be limited unless deployed alongside other tools, such as mosquito nets, better diagnosis and healthcare infrastructure.
"We cannot let excitement [about a possible vaccine] ... divert attention away from the need to invest in these prevention and treatment methods," she added.
Pharmaceutical giant GlaxoSmithKline has said its malaria vaccine, if given the market go-ahead, will be priced at the cost of manufacture plus five percent.
The five percent margin will be reinvested in malaria research, the company said.