The Trimbos addiction research institute says the use of mini waterpipes known as shisha pens is not to be recommended because of the likely impact on health.

The electronic cigarettes, which come in fruit flavours and different colours, are becoming a cult among children as young as 10, according to recent media reports. This has led health minister Martin van Rijn to commission a report into their use and the associated health risks.

While the tubes do not contain nicotine or tobacco, they do contain glycerol and other chemicals which are inhaled and may irritate the lungs.

The Trimbos institute says the use of shisha pens is a worrying development because of the potential health risks and the fact that youngsters become used to the idea of smoking and inhaling smoke.

The pens can be bought online and in tobacconists. While the Dutch importer has recommended they are not sold to the under 16s, this is not compulsory.