The Philippines’ fiery President Rodrigo Duterte has lashed out at Oxford University as a “school for stupid people” after it published a study claiming he had paid for a cyber army to increase his popularity on social media.

The study, “Troops, Trolls and Troublemakers: A Global Inventory of Organised Social Media Manipulation”, looked at the strategies used by political parties and candidates in 28 different countries to spread their party messaging and inflate social media engagement numbers.

It claims that Duterte’s camp paid $200,000 (£150,000) in 2016, the year he was elected, for a social media campaign that used citizens and groups to promote and defend him online.