The massive police presence mobilised on Tuesday morning following the threat of a shooting at Leiden university was called off at noon.

The threat was made via social media where an anonymous message on an American forum read: Tomorrow at 10.05 I will open fire at the University of Leiden. I will not say which faculty; you will have to guess that yourself.

The unversity authorities immediately alerted the police who arrived to guard all the faculty buildings in Leiden and The Hague.

‘We do not see a reason to evacuate the buildings and lectures are continuing,’ a spokesman told Dutch media.

In April 2003, a youth was arrested in connection with a threat to shoot a teacher and a number of pupils at a secondary school in Leiden.