The government should demand that the £500m (€620m; $810m) it spent in 2009 on stockpiling oseltamivir (Tamiflu) be given back if it was found that the manufacturer withheld trial data that showed it to be no more effective than placebo, say MPs.

Researchers from the Cochrane Collaboration have claimed that the manufacturer, Roche, has conducted over 123 clinical trials but that at least 60% of these are unpublished, which means that they cannot properly assess the effectiveness or risks of oseltamivir.

Roche agreed in 2009 to make key trial data on oseltamivir available to independent scrutiny, and the BMJ is running an open data …