This first example was obtained from John Lewis, we have bought identical covers from Clippasafe.
Also sold on Amazon and eBay.
Boots sell a slightly modified form. A nursery Nurse has suggested that, being shaped like a nipple, it has a particular attraction to babies. We consider this to be extremely dangerous, as saliva resulting from sucking may gather inside the cover and provide an electrical path along the plastic pins to the live parts of the socket.

The slot featured in the covers from Clippasafe, Boots and John Lewis is provided to allow the earth pin of a plug to act as the removal tool for the cover.

As you can see from these photographs, the slot also allows access to contact the live part of the socket using our needle test probe. 

To understand how this can be, we have cut away a cover to show a view of what is going on under the dome. You can see that the cover plate only makes contact with the socket around its edge. internally there is a space between the surface of the socket and the underside of the plate, this space, combined with the chamfered edge of the socket hole , allows free passage for the probe to be inserted alongside the live pin. (The edge is chamfered to allow plugs to be inserted easily.)

It is not possible to insert any foreign object into a BS 1363 socket with the shutters closed. However, the use of a socket cover allowing access to the live parts renders this socket, and all others, unsafe in a similar way to the type shown below. The cover could easily have been designed in a way which would make such access impossible. Boots have told FatallyFlawed that in excess of 4.5 million of these covers have been sold, that will have created 4.5 million dangerous sockets.

It appears that in adapting it to fit a UK socket the “power pins” have been placed right at the edge of the plate, (BS 1363 requires pins to be 9.5 mm from the edge).  As a result the sockets are not completely covered leaving an unshuttered hole into which a paper clip or similar can be inserted, making direct contact with a lethal 230 volts! 

The internal shutters of a BS 1363 socket are there to prevent such foreign bodies being inserted, and it is not possible to do this in the absence of a cover.

This cover was obtained from IKEA who call it the PATRULL.

The cover plates are quite flexible so it is very easy to push in upside down. 

The red version appears to be intended for use as an extractor for the white one (although we found they were easy to remove without), a pictogram on the packet warns not to put it in a socket, but dimensionally it is identical. We think the red colour makes it particularly attractive to small children.

Those we bought were in a packet bearing a photo of a US socket cover on the front, but the basic design of the plate indicates that it was originally for continental sockets (they are made in Holland).

The is the same design, but bought from Mothercare under their own brand. Those we bought were a shiny grey colour which we think would attract children, but Mothercare appear to now offer a white version. 

As with the IKEA model, this design leaves the sockets partially exposed when the cover is inserted normally.

This is a cover marked “KIDDI PROOF PRODUCTS” which was found being used by a play group.

We do not know if it is still being sold, but it is particularly dangerous.

Although not so obvious as in the type illustrated above, we found that the cover is too small to prevent paper clips etc being inserted as shown below - only possible because the cover opens the internal shutters.

 The picture left shows a shaped earth pin which catches on the edge of the socket hole and effectively locks the cover in place, shutters open, when inserted upside down! 
We understand that the intended function of this pin is to increase the friction exerted on the earth socket, making it harder to withdraw, it appears to be based on a UK patent GB2220803. We could not detect that this actually works - except when inverted. 

We purchased this model, marked PMS through Cablestar, an online supplier, via Amazon. Cablestar have become the first retailer to cease selling covers when we brought the danger to their attention. The packet was labelled “Mercury Telecraft Ltd.”

We have also seen this model on sale at Maplin, it has the shortest lower pins we have yet seen at less than 2/3 of the standard length. Even though it is not very flexible the short pins make it particularly easy to insert upside down.

This is from an unknown source and was found in a hall used by a playgroup. 

The cracks you see were present when it was found and they allow the earth pin to be fully inserted, upside down, without difficulty.