A majority of MPs support the use of a special spray in secondary schools which can be used to identify drug users. Justice minister Ernst Hirsch Ballin told MPs on Wednesday his department is investigating whether the spray actually works and its legal implications.

The spray, which comes from Israel, is said to change colour when it comes into contact with cannabis, cocaine and ecstasy. Its use is being advocated by a group of parents from the town of Volendam whose children have drugs problems.