Geert Baudewijns, a cyber security expert working for a company called Secutec, who travelled with the group, says: “We knew we would be attacked. We just didn’t know how far they would go.”

Mr Baudewijns recorded 135 attacks per hour last Monday: “The attacks were carried out using bots. It’s not an unusual technique, but we hadn’t expected so many attacks. The number of attacks in Belgium from Chinese sources is limited.”

Several of the companies taking part in the trade mission are Secutec clients. Mr Baudewijns also advises the Belgian authorities on cyber security.

The Belgian delegation was well prepared. Ministers had been briefed. The mission head, Princess Astrid, had been notified what action to take. Delegates used throwaway mobile phones. Geert Baudewijns believes some participating companies may have underestimated the threat: “I can only advise people to reset their equipment and change all passwords!”

Based on his experience in China Mr Baudewijns now also intends to formulate proposals for future trade missions. During the journey he employed the honey-pot technique using protected and unprotected equipment to identify the nature of the attacks. Attempts were also made to install spyware that could be used on the Belgians’ return home.

Geert Baudewijns believes Chinese state security may have been behind the attacks and that it was out to obtain politically-sensitive information, passwords as well as product information.

Belgian state security too had warned delegates of the threat beforehand and had advised precautions.