British pharmaceutical giant GlaxoSmithKline (GSK) has announced that it will stop paying doctors to promote its products, in a first for a major drugs company.

The company will also end the practice of paying for healthcare professionals to attend medical conferences.

Such incentive schemes are a common practice in the pharmaceutical industry, but have been attacked by critics who say they compromise doctors' impartiality.

GSK is also being investigated over £320m in alleged bribes to doctors in China, but the company said the new measures were not related to the claims.

It is estimated that British doctors are paid around £40m a year by pharmaceutical companies in flights, hotels, travel expenses and service fees.

Sir Andrew Witty, CEO of GSK said the measures would "modernise our relationship with healthcare professionals."

"These are designed to bring greater clarity and confidence that whenever we talk to a doctor, nurse or other prescriber, it is patients' interests that always come first," he said. "We recognise that we have an important role to play in providing doctors with information about our medicines, but this must be done clearly, transparently and without any perception of conflict of interest."

Changes will also mean that GSK sales representatives' pay will no longer be linked to the amount of prescriptions doctors write for their drug. 

The Association of the British Pharmaceutical Industry said that all UK drugs companies were "committed to increasing the transparency of payments to medical professionals", with information on which individual doctors are sponsored by companies to be published in 2016.

Doctors cautiously welcomed GSK's pledge. Dr Vivienne Nathanson, head of science and ethics at the British Medical Association (BMA) said: "It is pleasing to see a large pharmaceutical company like GSK recognise that it can reduce the possibility of undue influence by rewarding employees for providing high-quality information and education for doctors, rather than for their sales figures."