Four drivers who picked up passengers using the Uberpop private taxi service in Amsterdam on Saturday night were arrested for acting as illegal cab drivers.

The four were caught out by transport ministry inspectors posing as passengers. They face fines of up to €4,200 which will be increased if they are caught offering taxi services again.

Taxis in Amsterdam have to have a licence and officials pledged to take action against Uber drivers when the app was launched in July.

It is the first time Uberpop drivers have been fined.

This summer Uber raised $1.2bn in extra financing to expand its operations, valuing the company at $17bn.

Uber Nederland director Niek van Leeuwen told Nos radio on Sunday evening the company would ‘fully support’ the drivers and would first try to establish what the legal basis for the fines is.