The president of the European patent office in Rijswijk near The Hague has walked out of a meeting with a Dutch minister after being irritated by the way he was being questioned, the NRC reports on Wednesday.

The paper says Benoît Battistelli left the office of junior economic affairs minister Martijn van Dam after half an hour. The paper bases its claims on patent office sources.

The patent office, which is based in the Netherlands, Germany, Austria and Belgium has a workforce of 7,000. It has hit the headlines recently because of a conflict between Battistelli and the union SUEPO, which he refuses to recognise.

The patent office’s international management council will vote on Wednesday on whether or not to set up an independent inquiry into the way some union members have been treated, the NRC says.

The Dutch minister is said to have raised working conditions and the damage to the patent office’s reputation during the meeting with Battistelli at the beginning of this month.

He accuses the union of slander and says his position is supported by most member states. When Van Dam repeated his concerns, Battistelli broke off the conversation and walked out, the sources said.