The Chinese authorities are stepping up scrutiny of the prices of medicines from western pharmaceutical groups, against a backdrop of growing evidence they are often charged substantially more than richer countries.

One analysis conducted last year by officials showed 31 imported drugs were offered for sale in China at an average of twice the UK price, according to Tsung-Mei Cheng, a health policy research analyst at Princeton University with strong contacts in Beijing.

Several other similar studies were prepared in advance of regulators’ recent probes into multinational drug companies about pricing and corruption. GlaxoSmithKline. AstraZeneca, Lundbeck and most recently Sanofi have received inquiries from the authorities in regard to marketing practices.