A friend from Beijing was in Brussels about two weeks ago to attend a business meeting, and before departing for London on June 20 afternoon, he told me at the Brussels airport, which suffered a deadly terrorist attack 15 months ago, that, "Europeans have a short memory".

What he meant was that people are no longer required to undergo security checks before entering the airport.

On March 22 last year, Brussels suffered two terrorist attacks - one at the airport and the other at the metro station close to the European Union headquarters - which prompted the authorities to make security checks mandatory at the entrance to the airport. But it was withdrawn a few months later. No such security checks were necessary at metro stations, though, despite the high-level security alert in Belgium.