It may be an apocryphal tale, but in the days of the Empire it is said that many passengers embarking for the tropics were persuaded to buy small packages labelled "Insect Destroyer", and further labelled with the instructions "do not open until required". When the packages were finally opened, it was discovered that they contained only two small blocks of wood and the instructions "Place the insect on one block and strike sharply with the other".

In these days of Consumer Protection and Trading Standards it might be hoped that this type of con is very much a thing of the past, but according to a report from the Electrical Safety Council, it is still very much with us. The latest manifestation is a range of "plug-in energy savers", normally sold over the internet pr at car boot sales.

These devices claim to save money on electricity bills by doing some kind of "conditioning" to the supply which makes appliances run more efficiently. This is nonsense. The Electrical Safety Council tested four different models, all of which actually increased power consumption rather than reducing it.

More worryingly, all the devices tested failed to meet basic product standards. In all cases the pin dimensions were not correct. This means that the device would be a loose fit in the socket-outlet, which would cause arcing and overheating. All the devices tested were also of poor internal construction, making them a fire hazard. Several of them were CE marked, but the poor quality of construction would suggest that these marks were almost certainly forgeries. 

There have been reports that these devices are also being sold over the phone. Many elderly people have been targeted by telephone sales calls purporting to originate with one of more of the energy suppliers. Often the caller has the persons' name and address, and on some occasions even part of their credit card number. These calls are bogus and originate overseas, many from a holding company in the USA.

If you should be offered one of these devices, Action Fraud ( would like to know. You can also contact them on 0300 123 2040.

- Mark Jenkins